Zimbra FAQ

This page tries to give some explanation about how you can use Zimbra to your advantage and what to watch out for.

Most of the local Zimbra information is presented deliberately on this single web page, to facilitate searching. To keep its load/display performance fast enough no screenshots are used on this page directly, but are only linked to.


Normal use

The Zimbra web interface is the recommended interface to your Zimbra Calendar and Mail.

Other interfaces can be used as well, but YMMV.

The web interface is available on https://zimbra.cs.kuleuven.be/

  • Log in with your departmental login name and password ... screenshot
  • Initial screen shows your Zimbra Mail. Here you will see invitations to meetings and you can react on it ... screenshot
  • Use the Calendar tab to see the Calendar view ... screenshot
  • Documentation: the Zimbra user documentation is available by clicking on the Help button
  • The language used by Zimbra can be changed using the preferences tab. (But only English and Nederlands are tested)
  • You can use the Zimbra web interface also to access other/external mail accounts ... in this way you can use Zimbra as a webmail client.

Zimbra Mail

E-mail is an essentiel component for Zimbra to make its calendar functionality work as intended.

  • In some emails you can do an accept/decline ?
    You can do the equivalent accept/decline in the calendar view.
  • Some mails only tell something is changed ?
    Indeed, no action is needed for these mails. But the orginator of those changes can add extra info to those mails, therefore you may need to read them.
  • Do you have to read all those mails ?
    Probably not, but that's your decision. The system will keep working. You should however clean up your Zimbra Mail from time to time, it will be stacking up.

We do not recommend to switch/forward your regular mail to user@zimbra.cs.kuleuven.be. For the time being, the Zimbra system should best be restricted to appointments.

To forward your Zimbra mail to another (external) mail address, edit Preferences -> Mail but when you do so, never check the button Don't keep a local copy of messages. If you would check that button your Zimbra calendar would never see invites from other users and thus would not register the meetings you are invited to.

Simple Appointment/Meeting

Use the New -> Appointment menu option or select/drag the desired time period on the Calendar view.

Only use the QuickAdd dialog for very simple appointments without attendees, locations or resources. Consider to disable the QuickAdd dialog in your Preferences -> Calendar.


Since the upgrade to zimbra version 7.2.3. in april 2013 you MUST click the SEND /VERZENDEN button,
rather than SAVE / OPSLAAN, when creating any type of appointment with meeting rooms, resources and/or attendees other than yourself.

Otherwise the invitation will not be sent and the appointment will not be scheduled in the other attendees' calendars and the meeting rooms and resources will not be reserved for you.

Request Responses / Send Notification Mail

Behind the scenes and often also very visible, Zimbra uses e-mail to communicate/schedule/modify/notify about meetings.

So it is probably best the let Zimbra do its thing and leave the Request Responses and Send Notification Mail options checked.

Only un-check these options when you know you don't need them. An example to un-check the Request Responses option is when you invite a (large) number of attendees and really don't care who or whether they accept to come or not. Likewise, un-check the Send Notification Mail option when you changed less important details about the meeting and don't need to signal this change to all attendees.


On the Find Attendees tab, you can search for and select attendees to invite to the meeting.

You should never ever type in a name or e-mail address of a Zimbra user yourself ... only select it as a result of a search or autocompletion. In this way, you avoid mistakes and you make sure your meetings do indeed refer to the right persons. This of course only goes for internal/departmental Zimbra users ... external users cannot be found using search or autocompletion unless you have added them to your private address book.

Because the Global Address List contains a large number of people, not all of them are shown initially. You will also get a similar warning when searching in/through the GAL yields too many results (see screenshot). You can disable the initial listing of the GAL when searching for attendees in the Preferences -> Address Book -> Options. Doing so, will get rid of the annoying warning when visiting the Find Attendees tab. You can also enable auto-completion to include the GAL in the Preferences -> Address Book -> Autocomplete.

When you do continue despite the warning/informational message and use the Add All button, not all attendees you intended to invite, will actually be invited ... only the ones currently shown will be invited, the others (that are not shown because the list/search yields too many results) are not.

A better way is to search for the right Distribution List and to add this list (e.g. dept-cw group in this screenshot).
And finally since you are probably not interested everybody is free, you do not need to annoy them requesting responses ... screenshot

Access Rights to Calendars

By default, as do other modern groupware systems, Zimbra does not allow access to (the details of) other peoples Calendars. The normal/usual way to schedule a meeting is by means of the Free/Busy information you do have access to (but see the section about Sharing Calendars as well).

The members of the secretariat however have read access to the calendars of every Zimbra user. This means they can open all calendars and read the public information contained in them, but not the private information!

Moreover, the members of the secretariat have read and write access to the calendars of (almost) every Zimbra resource/location. This means they can open all calendars and read and change all information contained in them, including the private information!

And some resources also have other responsible persons, that have access to their calendars, including the private information.

This means that even if you have set a specific meeting to be private, the people that have access to the calendars of locations or resources that are involved in that meeting, are able to see the details of it.

Using Free/Busy Times for Scheduling Meetings

The departmental Zimbra allows every user access to the Free/Busy times of every other user, location and resource. Please check/set this in Preferences -> Calendar.

You can see the Free/Busy time:

when creating or editing an appointment by means of the status field in the list of attendees
this view gives the status of all the attendees together on a particular time period (that of the appointment in question).
when creating or editing an appointment by means of the schedule function/tab
this view gives the status of all the attendees together on a single one-dimensional time scale that you can move back and forth (by changing the start and end times) and thus evaluate/look for the best time period.
by using this web interface to the free/busy information and fill in either Firstname.Lastname or the login name of the person in question
this view gives an overview of the status of a single person by day/week/month.

The web interface/third option is the closest you can get to the Open Agenda function of the old Netscape Calendar server.
The schedule/second option is the closest to the Open Group Agenda function of the old Netscape Calendar server.

Accept or Decline

You can choose what you want to do with an invitation both in the Mail and/or in the Calendar view.

Some invitation-mails clearly show the selected time period for the meeting in question, but some invitations don't. We currently have no idea why and/or how to prevent this. (there are some Zimbra bug reports, describing this or a similar problem: bugzilla - forum)

We do have a work-around however (a bit ugly though ;-): look at the source of such an invitation with hidden details (right click on the invitation in your Mail/Inbox and select Show Original), scroll to the very end and look for a line containing DTSTART ... next to that keyword you will find the start date and time of the meeting. What you are looking at right there and then, is the ASCII representation of the invitation, which is sent as an attachment with the invitation-mail. You can also find other details about the meeting you are invited to (attendees, location, ...)
Take care: don't just take any DTSTART line, there is probably also one describing the start of the entire calendar, which probably is something like DTSTART:19710101T030000.

Recurring Meeting

Make sure to check all available details because the default most probably is not what you want ... e.g. you most probably do want an end date.

Distribution Lists

Besides inviting individual attendees, you can also invite groups of people. In Zimbra such groups are called Distribution Lists. Which Distribution Lists are defined is available on the internal web server (only from within departmental networks or via VPN).

When inviting such a Distribution List however, it is not expanded in Zimbra to its individual members. As a result you cannot see who is available and who isn't.

Moreover, the invitations made with Distribution Lists end up in the Calendars of the people in the list, but you cannot see who did accept or decline unless you know who is in the list and have access to those peoples calendars.

The advantage of inviting a Distribution List is that when later on somebody is added to the list, she will be invited to all new meetings using the list and will get all changes to existing meetings in which the list is invited: the organizer needs to edit and save such existing meetings before they are visible in the calendar of new members.

When making invitations using Distribution Lists you might want to make sure some selected members of the group are still free such that they really can come. Distribution Lists do not expand in the schedule view, but you can add those selected VIP's by their (Zimbra) e-mail address. They will show in the schedule view with their Free/Busy time, thus enabling you to select a time period that suits all of them. The fact that you are inviting those people twice (once directly and once via the list) does not show up in their Zimbra calendar view ... they will see the meeting only once, no matter how often they are mentioned in the attendee list.

Distribution Lists are kept up to date automatically, based on information that is being used in other ICT infrastructure of the department as well (e.g. e-mail aliases, Unix groups, ...). If you want to have a specific group/alias added to Zimbra, just let us know.

Location and Resources

There are some locations (mainly meeting rooms) that can be booked/reserved. Most of these are quite clear what/how/when.

  • most rooms auto-accept a reservation unless they are already booked - you get a response (positive or negative) right away when booking
  • some rooms must be manually confirmed by the secretariat - you only get a response when they get to it
  • if you don't get a response right away, you should assume the room you are trying to book is of the latter kind - if urgent, you can check with the secretariat what the status of your booking is
  • room 01.112 has some special equipment, which is described in more detail elsewhere

There are also some special resources/equipment, some of them with additional guidelines:

  • handycam video camera
  • portable beamers and screen
  • some research groups have laptops or other devices

Locations and resources can only be reserved once for a specific time-slot: no double bookings are allowed.

  • With recent Zimbra versions, this does not apply to all-day meetings: all-day meeting-requests involving locations/resources can overlap with timed meetings with the same locations/resources
  • However, making an all-day meeting request involving locations/resources is considered bad practice because very few meetings do actually need a location/resource the whole day and reserving it that long might hinder other people
  • Therefore we discourage the use of all-day meetings when making reservations involving locations/resources

When making a reservation of a specific location/resource (by adding it as attendee of your meeting), you should pay attention whether it is free or busy.

Zimbra does allow you to make an appointment with a location/resource that is busy at the time of your meeting, but the location/resource will of course not accept (i.e. decline) your invitation.

You can see the (un)availability of a location/resource:

  • In the list of locations/resources where the label busy is shown ... screenshot
  • In the schedule where dark red blocks mark problems (= busy times of locations/resources/attendees) ... screenshot
    (the vertical green line marks the beginning of your meeting, the vertical red line marks the end)
  • In your Zimbra Mail where you get a message that the location/resource rejected your reservation ... screenshot

You should assume that the location or resource you are trying to reserve is not reserved unless you get an explicit Zimbra Mail confirming the reservation. When in doubt or when you want to know who has reserved a specific location or resource, ask the responsible person of the location/resource in question to check and confirm for you.

Take care: if you later on change the time period of the meeting in question, you risk loosing your reservation of the location/resource because that might not be free during the newly selected time:

  • When changing the time by Edit-ing the meeting, you will get a GUI warning, stating that the new time slot conflicts with another reservation of the same location/resource. You then have the chance/choice to either cancel your change or go ahead anyway (the latter is probably not a wise thing to do)
  • When changing the time by Drag-ing the meeting, you will NOT get a GUI warning: the change is indeed done, but the location/resource might have declined the new time-slot: check your Zimbra Mail: it will explicitly answer the new meeting-time: either accept or decline.

Once you have such an accept confirmation, it stays yours (first come first served) unless the responsible person of that location/resource explicitly/manually declines (the presence of that location/resource in) your meeting. Those responsible persons will of course only do such a thing if it is really necessary and will contact/notify you when they do so. Anyway, it might be a good idea to check your Zimbra Mail a little bit before a (important) meeting is scheduled whether you do have the confirmation Zimbra Mail that acknowledges your reservation of that specific location/resource and to keep that confirmation by hand just in case somebody else comes along and claims the same location/resource ;-)
If you have a confirmation mail, but also a (more recent) cancelation mail, you are out of luck: somebody else will have a more recent confirmation mail and you will have to look for a different location/resource.


We have a limited (in time) daily backup. Individual Zimbra users can be restored to the situation of the daily backup (complete restore: Calendar, Mail, Tasks, ... (but all or nothing restore, it is not possible to restore individual messages ;-). Please ask the helpdesk.


In the Zimbra Preferences, you can tweak your Zimbra to your liking ... but there are some settings that you shouldn't mess up too much. Most of these are described somewhere else on this page as well.


Do not change the Default Timezone: it should always be set to GMT +01:00 Brussels/Copenhagen/Madrid/Paris.

Do not Change your Password: at best, it just won't succeed, at worst, you will lock yourself out of Zimbra.

Your Zimbra account itself does not have a password; authentication is done via the departmental LDAP infrastructure and thus the password for your Zimbra account is the same as for your departmental account.


When forwarding Zimbra Mail to another e-mail address, make sure that you disable/un-check the Mail -> Receiving Messages -> Don't keep a local copy of messages options because otherwise the Zimbra Calendar functionality will not work.

Consider to disable/un-check the following preferences:

  • Mail -> Displaying Messages -> Display snippets of messages in email list

Address Book

Consider to disable/un-check the following preferences:

  • Address Book -> Options -> Add new contacts to "Emailed Contacts"
  • Address Book -> Options -> Initially search the Global Address List when using the contact picker

Consider to enable/check the following preferences:

  • Address Book -> Autocomplete -> Include addresses in the Global Address List


Consider to disable/un-check the following preferences:

  • Calendar -> General -> Delete invite on reply
  • Calendar -> Creating Appointments -> Use the QuickAdd dialogue when creating new appointments

Consider to enable/check the following preferences:

  • Calendar -> General -> Calendar -> Automatically add received appointments to calendar
  • Calendar -> Permissions -> Free/Busy -> Allow both internal and external users to see my free/busy information
  • Calendar -> Permissions -> Invites -> Allow both internal and external users to invite me to meetings

Advanced Use

Sharing Calendars

Everybody can change the access rights of its Zimbra folders and can share folders with other users. In this way, you can give some people access to (the details of) your Calendar.

But think twice before you consider to do that ... there are a number of ways in which the Free/Busy information might be enough, eliminating the need to actually give read access to your calendar to somebody.

And before starting to give a whole bunch of users access to your Calendar in the way described below, please consult with helpdesk because we have set up an automatic way for doing so. Using that automatic procedure, you can ask to have your Calendar shared with a Distribution List (e.g. your research group or a well known subgroup) such that new members of such a list also get the same access rights automatically. Otherwise you have to remember to do it manually every time somebody leaves or enters the group.

Conclusion: it is probably wise to consult with helpdesk before enabling/experimenting with sharing.

Moreover, Zimbra has 2 levels of access: public and private. When sharing, you have a choice to only give access to your public information or also to your private information. As long as you don't share your Zimbra data, it doesn't matter what level you assign to your appointments etc. But when you start sharing your Zimbra data, you probably want to take a moment and make up your mind what you want to do with these access levels.

To share your calendar:

  1. Click on the selected calendar name in the navigation frame and select "share calendar" ... screenshot
  2. Fill in email (user@zimbra.cs.kuleuven), role and options allowed for the other user ... screenshot
  3. Click OK to export.
  4. Exported calendars can be shown and changed by clicking on the calendar name in the navigation frame and selecting edit ... screenshot

To view the calendar of another user either accept the invitation that was sent to your Zimbra Mail or:

  1. Click in the navigation frame on the left in the "Calendars" section on the "Find shares..." link ... screenshot
  2. In "Find shares" fill in the login name, press Search and select the Calendar
  3. Click Add and now the user's calendar events will show up ... screenshot
  4. You can change the color of the calendar as usual: right-click and select Edit properties

Besides /Calendar any other Zimbra Folder can be shared, e.g. /Inbox (for mailboxes).

A good example of shared calendars are the out-of-office calendars that are/can be created to share only some information (of a group of people) with a selected group of viewers.

External Calendars in Zimbra

You can add external, but read-only, calendars to your Zimbra account. Two-way syncing is not possible, it is only possible to view shared calendars.

Shortcut: if you are looking how to include the official KU Leuven Holidays you most probably will want to import them.

There are 2 ways of adding such external calendars to your Zimbra:

  • import them:
    • Advantage: you don't need the original version anymore after you have imported it
    • Disadvantage: if the original changes, you will not automatically see those changes in your Zimbra calendar but you will need to re-import the external calendar
    • Disadvantage: you cannot selectively hide or show this calendar
      (unless you create a new calendar just for the purpose of storing the imported (events of a) calendar)
  • link to them:
    • Advantage: if the original changes, you will see those changes also in your Zimbra calendar
    • Advantage: you can selectively hide or show (the events of) this calendar
    • Disadvantage: from time to time Zimbra will try to reload this calendar, which will give errors if the original disappears or is unavailable at the time of resyncing or needs authentication when accessing it

If the external calendar rarely changes, you probably want to import it ... if it changes regularly, you probably want to link to it.

To import (the entries in) an external calendar into one of your existing calendar(s), first copy or download that calendar into a local file and then:

  • Login to your Zimbra
    • Select the Preferences Tab
      • Select the Import/Export function on the left menu
        • Select the File to Import
        • Select the Destination calendar to Import into (Calendar is your default Zimbra calendar)
        • Click Import
        • ... screenshot

    Instead of the default Calendar, you can import into a new calendar that you create specificly for this imported events (you need to first create it and then you can specify it to import into). In this way, you can show or hide this imported external calendar as you like.

  • A good example of a calendar to import are the official KU Leuven Holidays. Information about and links to them can be found on the KU Leuven Intranet
    • you cannot link/refer to the KU Leuven ICTS version directly because they are password/Shibboleth protected
    • you should copy the .ics files locally and then import them from there in your Zimbra calendar as described above
      • if you do not want to import them, but really want to link to them, you should copy them to your personal, internal web space and link to them from there as described below
    • you most likely only need either kuleuvenYYYY_nl.ics or kuleuvenYYYY_en.ics, since the other information is primarily intended for the KU Leuven Exchange users
    • if your primary work address is Campus Kortrijk, you might want the campuskortrijkYYYY.ics or campuskortrijkYYYY.ics instead ;-)
    • ... screenshot
    • after importing them, you can check the import on February 2nd ... it should be marked as Patroonsfeest
    • moreover, all KU Leuven holidays of YYYY have as Location: KU Leuven YYYY
    • KU Leuven ICTS will (probably) make updated or new versions each year as soon as KU Leuven administration decides on the exact dates ... in all of the above, you can probably change YYYY into the current year you are reading this + 1 (but they might of course adopt a new naming scheme in the future so check before clicking).

To link to an external calendar:

  • You need the URL that points to the ICAL/ICS file/representation of the calendar in question:
  • Login to your Zimbra
    • Go to the Calendar tab
    • Select Add external Calendar
    • Select Add external Calendar (other)
    • Select Next
    • Select type iCAL Subscription
      • Paste the ICAL/ICS URL for the external calendar into the URL box
    • Select Next
    • Give it an appropriate name
    • Consider whether or not to check "Exclude this calendar when calculating free busy times".
    • Click OK

External, linked calendars are refreshed/reloaded:

  • automatically every 6 hours if you enable synchronisation in the properties of the calendar
  • manually when you right-click them and select the Reload option.

Example of calendars you might want to link to are:

  • BTW: http://iwww.cs.kuleuven.be/~btw/Zimbra_alm_XX-YY/loginname.ics
    • Replace XX-YY in the above URL by the academic year you want (e.g. 13-14 for 2013-2014)
    • More information about BTW on Zimbra can be found on the BTW web site.
  • Google: http://www.google.com/calendar/ical/google-private-ical-calendar-address/basic.ics
    • The google-private-ical-calendar-address is what you can find by clicking the down arrow next to your calendar at calendar.google.com and selecting 'Calendar Settings'. Locate the ICAL button next to the Private Address label at the bottom of the page and note/select the link it points to.
  • Belgian/Flemish School Holidays 2009 - 2024: schoolvakanties.ics
  • Corrected week numbers 2010:
    • as week events for the years 2004 - 2016: Weeknumbers.ics
    • as day events on Monday for the years 2008 - 2010: Kalenderwochen_2008-2010.ics
    • don't forget to disable/un-check in Zimbra Preferences -> Calendar -> Show Calendar Week
      (You wouldn't want to see the wrong numbers when you known they are wrong, don't you ;-).
    • because of different standards for numbering the weeks in the year [1][2], in 2010 the standard used in Belgium/KU Leuven (ISO 8601) is not the same as the standard Zimbra uses ... therefore these explicit calendar-entries that show the numbering as it is used at (a.o.) the KU Leuven.
    • I have not checked for which years the Zimbra standard deviates from the standard used at the KU Leuven ... if you happen to know it, please let me know ;-)

External access to Zimbra Calendars

You can add/view your Zimbra Calendars in Google Calendar. Two-way syncing is not possible, it is only possible to view shared calendars.

In order to setup a calendar in Zimbra to be shared with Google, do the following:

  1. Right click on the calendar you want to share from the list on the left side of the screen
  2. Choose Edit Properties, then click Add Share...
  3. Change the type to Public (view only, no password required)
  4. Copy the URL at the bottom of the window (such as https://zimbra.cs.kuleuven.be/home/USERNAME/Calendar)
  5. Click Ok, then click Ok again

To add the calendar to Google Calendar:

  1. Click Add, then Add by URL
  2. Paste in the Zimbra URL from above
  3. Add /?fmt=ics to the end of the URL (so the entire URL will look like https://zimbra.cs.kuleuven.be/home/USERNAME/Calendar/?fmt=ics )
  4. Click Add

Be aware that in doing so, you open up access to your calendar to everybody that knows your USERNAME !

Mobile Devices and Other Client Software

User interfaces

To check whether a specific client software or mobile device embedded software is able to correctly communicate with the Zimbra server, you can use some use cases.

  • Zimbra announces a Free Yahoo! Zimbra Desktop (YZD) on its web pages. You can use it, but read on:
    • It uses HTTPS to access your calendar and mailbox on zimbra.cs.kuleuven.be. This will work from outside the department.
    • It has a major security problem. It stores your login and password on your local computer; we do not know how and we do not know how to switch this off. If somebody has access to your laptop everything accessible with your login and password is at risk !

  • Can I look at my calendar with a simple browser ?
    • Try https://zimbra.cs.kuleuven.be/home/USERNAME/Calendar.html?start=-14d&end=+14d
    • The start=-14d&end=+14d limits the range shown in the display. This also works for .ics files.

  • Access Zimbra from your favorite/personal mobile device/PDA
    • "Mobile Sync" or "Active Sync" is enabled for all accounts.
    • Exchange/Active/Mobile Sync is probably licensed from/by Microsoft. Check their FAQ.
    • One user reported he lost his complete calendar using Active Sync:
      • Windows Mobile only uses one server to synchronize and does not care were an event comes from.
      • The events already on my calendar (by syncing through e.g. Google Calendar) did show on my PDA, after starting active sync.
      • I saw every appointment twice and made the mistake to wipe all events on my PDA. Then I did "active sync" synchronize with Zimbra.
      • Result a completely empty calendar.
      • Luckily there is backup from which to restore ;-)
  • Thunderbird via CalDAV - Under test, seems to work. Note however:
    • When thunderbird synchronizes with your calendar it may become slow.
    • There is no good support for locations and equipment.

  • MacOS-X Ical via CalDAV - Works (Koen Poppe)
    • Some users report a fully operational behavior, other report problems. (We look for a reproducable error and/or errormessage: see testsheet).

  • Microsoft Outlook - Works (with Zimbra-Outlook connector, Bert Lagaisse)
  • ...

Known Issues

  1. I get a zillion emails about the same meeting

    Each time the organizer saves a meeting, even without changing anything, all attendees are notified of this new version. Because Zimbra uses email to communicate even internally, you will notice these emails in your Zimbra Mail.

    Organizers should therefore try to limit the number of saves as much as possible: try to get everything right from the beginning ;-)

  2. Can I have the Calendar or Contacts tab open instead of the Mail tab when I log in to Zimbra?

  3. I received an email with a calendar invitation in my cs.kuleuven.be mailbox

    Technically you received a mail with a .ics attachment. To get that invitation in your Zimbra Calendar you can:

    • Forward that mail (as attachment !) to your zimbra email address (login@zimbra.cs.kuleuven.be)
    • Or you can Redirect (Unix terminology)/ Bounce (MacOS terminology) to your zimbra email address.

    Zimbra will handle that mail as an invitation with external attendees.

  4. My zimbra screen looks completely different from your examples ?

    In the login window you can select AJAX, HTML or Mobile. Use Ajax by preference (our examples use Ajax). Use Html when your browser does not support AJAX, some features will not be available any more. Use Mobile on small screen devices.

  5. Can I use todo/tasks ?

    When using the Web interface, yes.
    When using the Caldav protocol (Thunderbird, Ical), No; the synchronization produces strange effects.
    When using active sync (for mobile devices ), No or one can use tasks on your mobile device, but switch off synchronization for tasks.

  6. I did accept an invitation and now I have to accept the same meeting again ?

    When the organiser of a meeting changes anything on a meeting, all accepts for that meeting are destroyed and should be confirmed again.
    This is annoying when the change is about e.g. a small correction in the text.
    We are looking if this can be alleviated.

  7. Some recurrent calendar events are not synchronized to my mobile device ?

    You are probably using "active sync"; During the conversion from Netscape Calendar Jean did use the RDATE implementation since this allows random dates. Zimbra and  possible "active sync" use RRULE format for recurrent events. The old Netscape recurrent events are not synchronized by active sync.

  8. I try to reserve a resource for more than 200 days ?

    Do not try this. There is a limit of 200 days on the Free/Busy information, and the device will show up as free.
    Limit your calendar events to less than 200 days. We are looking if Zimbra can be forced to return busy in this case.

  9. Strange effects with distant timezones ?

    When using the web interface with AJAX, zimbra is able to read timezone/date/locale from the connecting device and the time and dates will be displayed accordingly.
    When using the web interface without AJAX (html or mobile) zimbra is not able to get this information and will display times and dates in its own format, currently GMT +01:00 Brussels / Copenhagen / Madrid / Paris.
    When switching between HTML and ajax you may see time jumps.
    Workaround for this AJAX feature: do not switch Ajax on and off or set your connecting device in Brussels timezone.

  10. I am using Firefox and in my Zimbra Calendar view I see all appointments multiple(4) times ?

    It is not clear what causes this, it may even be triggered by the actions of other users. One user got this problem when testing with Macos Ical and recurrent meetings, he even got "out of RPC cache" from zimbra.

    1. In the navigation frame (left) you will see "Calendar" twice. Deselect both "Calendar"s.
    2. Select another tab e.g. mail.
    3. In the browser reload the Page.
    4. select the calendar view. You should see only one "Calendar".
    5. Select "Calendar" and your calendar view should be normal.

  11. When zimbra is down, e.g. for maintenance or kernel installations, your browser may show the warning in this screenshot.
    Be patient and (eventually) warn the helpdesk.

  12. In 2010 zimbra uses wrong weeknumbers ?

    Indeed zimbra does not follow the European ISO standard. This is bug 12288.
    Workaround: See under External Calendars

  13. Synchronisation with Zimbra from my Windows Mobile 5 device does not work any more, I get "Certificate Expired"

    Zimbra.cs.kuleuven recently got a new Certificate from TERENA -> AddTrust (because kuleuven gets its certificate from a new  authorothy).
    The problem could be solved by installing a new root certificate for AddTrust CA Root on the mobile device. (Probably limitid list of root certificates.)

  14. Creating new events/meetings in Zimbra via iCal from a recent MacOS-X (reported on/with Mountain Lion) fails.
    There is a work-around (originally found/described on: https://mailman.stanford.edu/pipermail/macosxsig/2012-July/000970.html):

    • change the "Alerts" preferences in iCal to something other than "None"

Differences with Netscape Calendar

No access to Calendar details

See the sections about the default Zimbra Access Rights and Free/Busy information.

Appointments with groups/distribution lists

When inviting a group, the Netscape Calendar would expand that group such that you really invited the individual people in that group.

Zimbra does not expand the group, but instead invites the group/distribution list as such.

For more information, see the explanation about Distribution Lists in Zimbra.

In Netscape Calendar you had to remember to add new people of a group to all existing meetings with that group. In Zimbra you do not need to do that anymore: Zimbra will make sure that all meetings in which a list is invited, also show up in the Calendars of new members of those lists.

Appointments with locations/resources

Zimbra allows you to make an appointment with a location/resource that is not free ... the location/resource will of course not accept your invitation ... Netscape Calendar did not allow you to make such appointments. See the sections about the locations and resources for more information.

Access Rights to Appointments

Zimbra has 2 access rights for appointments (private or public). Netscape had 4 values (private, confidential, normal and public). During conversion private and confidential are mapped to private, normal and public are mapped to public ... screenshot


Zimbra uses shares of folders instead of delegates for calendars. No automatic conversion was attempted. We do have set up some defaults however, see the section about access rights and/or sharing.

Known Issues with Converted Data

These issues are caused by the conversion of Netscape data to Zimbra ... they are therefore only relevant for converted data and will fade out.

  1. My todo/task list was not converted from Netscape Calendar ?

    The icalendar format we did use during conversion did not include tasks, although it should/could. We can convert Tasks using vcalendar and some scripting. Please ask Helpdesk or jean if you did use tasks. (until January 2010).

  2. The location of my meeting is not visible ?

    This is a side effect of the conversion from Netscape Calendar and will disappear when Zimbra is more used.
    During the conversion only known locations were converted and "unknown" text locations (e.g. "kasteel", "Blauwe zetels", "thuis") were left out.
    To make the converted locations visible in the web interface try to open the meeting and close it with save=yes. (This sometimes causes Zimbra to regenerate the location field.)

  3. When accepting or declining an invitation made in the old NSCAL system, I get an error message:
    Unknown error  (mail.INVITE_OUT_OF_DATE)
    method: SendInviteReplyRequest
    msg: The specified Invite is out of date (has been updated):
    code: mail.INVITE_OUT_OF_DATE
    detail: soap:Sender

    Body: {
    SendInviteReplyRequest: {
    _jsns: "urn:zimbraMail",
    compNum: 0,
    id: "9677-9676",
    m: {
    e: [
    0: {
    a: "denise@zimbra.cs.kuleuven.be",
    t: "t"
    1: {
    a: "ronald@zimbra.cs.kuleuven.be",
    p: "Ronald Cools",
    t: "f"

    This is (probably?) a side effect of the conversion from Netscape Calendar and will disappear when the old invitations disappear. We did add attendees for locations and changed some internal ID's during this process. Therefore Zimbra can not locate the original invite. Sorry.

    Workaround for the organizer : open the meeting, edit and change minor details (e.g. a space); zimbra will sanitize the meeting.
    Workaround for the attendee : send an ordinary email to the organizer of the meeting.

  4. I have a meeting which has no attendees, no location and I cannot change it ?

    This meeting was probably made in the old Netscape calendar and was destroyed during the conversion. Delete the meeting (using cancel) and make a new one or ask the organiser (if known) to make a new one.

Links to Other Documentation

If you don't find an answer to your question here, you can also try: