After updating vSphere and all the components, including VMware Update Manager, I started getting an error when trying to enable VUM in the vSphere Client.
After looking at several KB and a few posts on the internet. I couldn’t quite find the perfect one that fixed my issue. So through trial and error, and fixing this error in several of my environments, I discovered a process that worked for me. Hopefully it will work for you too.
The first thing I did was run the vSphere Update Manager Utility and update/reapply the database settings.
Next I went into SQL Management Studio for where the Update Manager Database was and look at the users associated to that database.
Finally I added the user I used in the vSphere Update Manager Utility and gave that user db_owner rights on the database. More than likely db_reader and db_writer would have been fine as well.
After these couple of steps I restarted the Update Manager service, and everything worked like a charm!
Hope this helps!