In the past I blogged about an issue that typically surfaced during an OCS 2007 R2 install on Server 2008 R1.
Due to a operating system deadlock condition, on some but not all servers, the server would stall at "Applying User Settings" until all services that would depend on http.sys or crypto time out. It was especially painful on OCS Front End servers because almost every OCS service would have to hang and timeout before a usable desktop would appear.
The good news is that you no longer have to use the workaround that changes service dependencies.
Trust me, it was an extremely annoying issue to debug when it first occurred at an on-site install.
The networking stack would not start up when this issue triggered, which meant using a remote management console or direct console access.
To be clear, it wasn't an OCS 2007 R2 issue, it was a Server 2008 R1 issue that could deadlock in certain scenarios. The most common scenario was OCS 2007 R2.
You can just apply the Server 2008 R1 hotfix from
here and never worry about it again.