Here's a link to the Zimbra Desktop 2 FAQ
Zimbra Desktop 2 FAQ - Zimbra :: Wiki
Here's a link to where the data is located, and a section of faq,
Zimbra Desktop 2 FAQ - Zimbra :: Wiki
Where is the user data location?
Each user's data is under her standard data location on the respective platforms are as follows:
* Windows XP - C:\Documents and Settings\<username>\Local Settings\Application Data\Zimbra\Zimbra Desktop
* Windows Vista and 7 - C:\Users\<username>\AppData\Local\Zimbra\Zimbra Desktop
* Mac OS Leopard and Snow Leopard - /Users/<username>/Library/Zimbra Desktop
* Linux - <home>/zdesktop
where <username> is the username of the user and <home> is the home directory of the user. In the rest of this FAQ we will refer to the user data location as <data>.
A little farther down in the FAQ, there's a description of where the log file is:
log file located at <data>/log/zdesktop.log
Here's a section on how to start the error console
What additional information can I collect to debug a UI display issue?
In the Zimbra Desktop UI window, use Shift+F6 to reveal the status bar on the bottom. Click on the Settings icon at the right end of the status bar and select Tools -> Error Console. Then click "Errors" on the top to filter out non-error information. If there are any errors they will be helpful in debugging your issue.
There's also a section in the FAQ on when things go wrong, as well as what to look for in log files, what to post, etc
Good Luck! Let us know what you find!