An issue has recently popped up in support. We have documented it on the following TechNet Wiki
TROUBLESHOOTING: stopped-server (Event ID: 6311 and 6401): http://social.technet.microsoft.com/wiki/contents/articles/10930.troubleshooting-stopped-server-event-id-6311-and-6401.aspx
In response to the below comments:
- This might work to help you get by on the SharePoint User Profile Synchronization Service. However, there could be an underlying problem, so you may want to contact support.
- The 4.0.2450 build is a build of the Synchronization Service Engine that is behind another product such as the SharePoint User Profile Synchronization Service.
Let me know if you have any questions.