- The User Profile Synchronization Connection had vanished
- After tearing down the UPS as recommended by all articles we came across, and rebuilding it, the service was still failing to start.
- After going through all setup and credentials several times, it would end up in the same situation: Stuck on "Starting".
After troubleshooting for 20 hours, we came across an article that would make all the difference - but it might be different for you.
But here is a word of advise: follow the articles steps in every detail. Don't think you know better unless you actually know better.
Here are the articles that helped resolve our issue - which was that we had to set the FIM services to "Local System" before starting the service. This fixed our problem. And know that UPS is so unstable in the setup/provisioning phase that it MIGHT fail, and hang at starting, even if you did the setup correctly. If it does this, and you tried everything in these articles, try it again!
- Configure profile synchronization (SharePoint Server 2010) (2013 is also there)
- Rational Guide to implementing SharePoint Server 2010 User Profile Synchronization
- “Stuck on Starting”: Common Issues with SharePoint Server 2010 User Profile Synchronization
- User Profile Service Stuck on Starting - This one was the game changer for us!
You should find the answers in one of those articles! - if not, then maybe your problem is not with the UPS!