When you are running Citrix Provisioning Services you might run into this problem after this weekend :
“The clocks on the client and server machines are skewed”
As a result Group Policy Objects are not applied.
This problem appear when daylight savings time goes into effect.
Citrix wrote a kb article about it : http://support.citrix.com/article/CTX123336
I also found an excellent PDF concerning this problem on the internet, link : http://www.neton.ag/wp-content/uploads/2009/02/fixing-the-daylight-saving-time-issue-in-citrix-provisioning-server-environments-v1-1.pdf
The timezone information is maintained in the Windows Registry located at : HKLM\System\CurrentControlSet\Control\TimeZoneInformation
In the following screenshot you see the value ffffffc4 which means wintertime is being used. ffffff88 stands for Daylight Saving Time.
There are multiple solutions, the workaround Citrix mentioned and the workarounds mentioned in the PDF-document. The first is booting the vDisk in Private Mode, the second is to create a script to change vDisks automatically.
More information on srvany.exe & intsrv.exe : http://support.microsoft.com/kb/137890
Thread on Citrix forum : http://forums.citrix.com/message.jspa?messageID=1414630
Microsoft kb article about GPO’s not being applied : http://support.microsoft.com/kb/886516
I got this link from @Easi123 (search for daylight) : http://support.citrix.com/servlet/KbServlet/download/25649-102-649146/Provisioning%20Services%205%206%20Best%20Practices%20External%201.2.pdf
Note : I remembered reading something about this issue from (a tweet or blogpost) Ingmar Verheij but I can’t see the link or tweet anymore. You can find his blog on http://www.ingmarverheij.com/