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.

timezone01

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/