Event ID 17 is logged in the System log on a TS Licensing server
Just a heads up that the issue around Event ID 17 being logged in the System log on a TS Licensing server has now been updated with a hotfix. Please refer to http://support.microsoft.com/kb/983385/ for updated guidance though heres the synopsis from the article.
"...On a computer that is running Windows Server 2003 Service Pack 2 (SP2), Windows Server 2008, or Windows Server 2008 R2, the Terminal Services Licensing (TS Licensing) server or the Remote Desktop Licensing (RD Licensing) server becomes deactivated, and only temporary licenses can be issued.
Additionally, the following event resembles an event that is logged in the System log:
Event Type: Warning
Event Source: TermServLicensing
Event Category: None
Event ID: 17
Computer: computer name
One or more Terminal Server Licensing certificates on server computer name are corrupt. Terminal Server Licensing will only issue temporary licenses until the server is reactivated. See Terminal Server Licensing help topic for more information..."