Terminal server 2008: Access denied error and eventlog not starting

On our teminal server 2008 farm we had some serious problems the last couple of days. Whenever users tried to login they got a “Access Denied” error. Only administrator accounts were able to log in. Additionally the eventlog, the McAfee services and some other services weren’t started automatically.
It was even not possible to start the eventlog manually.

We saw this issue on all our Terminal servers once they were joined to the domain. We finally nailed down the cause of these problems to be an group policy who configures the language settings.

Apparently this GPO changed also the language settings for the local system account. Which caused these services not to start anymore.

Pieter Wigleven posted already about a similar problem he had with Hyper-V and how he fixed it.

Update: Microsoft released a hotfix for this problem: KB951430.