Note: I've added an update from the nice folks at Vision Works Solutions to the end of this post. The complete information they sent along is in the comments, but I added it to this post so the information doesn't get overlooked.
Earlier today, I ran across an interesting issue - apparently several (mostly small - several running SBS) organizations have run into issues where Exchange ActiveSync or Entourage client sync fails when there are more than just a couple (and I mean as few as four) items in a folder. There is no correlation between the inability to synch and a specific folder or folder type - the issue has happened with contacts, the calendar, and just the standard Inbox folder. There aren't neessarily helpful error messages associated with this issue - timeouts are often seen, and the hex value 0×85010014 has also been seen.
This issue often is related to a third-party kernel driver - famv4.sys (File Access Manager, from Vision Works Solutions, Inc.). This file is used by some backup vendors to allow backup software access to open files. Generally, the backup vendors using this file are smaller vendors instead of the big-name software companies.
To isolate whether famv4.sys is causing problems with synch operations, you can disable famv4.sys through the registry:
- Open regedt32 (or regedit, whichever) on the server
- HKLM\System\CurrentControlSet\Services
- Find "famv4" (no quotes)
- Change the value of "Startup" for famv4 to 4 (this disables the service)
- Close the registry editor
- Open a command prompt on the server
- Type "net stop famv4" (no quotes), hit enter
If your ActiveSync or Entourage (or both) clients can synchronize now, you've isolated the problem - the bad news is that your backup software isn't going to work right now, so make sure you either a) go back and re-enable famv4.sys in the registry or b) sort out a different way to back up the server -- which option you take depends upon what will work best in your environment.
If you experience this problem, you should contact your backup vendor to report the issue and request a fix. You may also want to contact Vision Works Solutions (link above) so they are also aware of the problem.
This problem is also discussed by someone who's experienced it here: http://www.mytechnicallife.com/2008/08/20/exchange-2007entourage-famv4sys-issue-summary-from-microsoft/
Here's hoping this one doesn't bite you.
(Question: Why is synchronization abbreviated sync instead of synch?? I really feel like the trailing "h" needs to be there; it just feels incomplete without it. So I use "synch" mostly. Except when I don't. I claim no reliability on this issue.)
Update:
File Access Manager allows backup applications to open exclusively opened files for backup. Several different backup software companies license our driver FAMv4.sys from us and distribute it.
This incompatibility is common with file system filter drivers and we already resolved the incompatibility in the latest release of File Access Manager. You can obtain Version 4.1.7 at the below link.
Updates can be found here: http://www.vwsolutions.com/FAM/trial.aspx
For any future updates or questions you can reach our support techs here:
http://www.vwsolutions.com/support/submitTicket.aspx