I upgraded my vCenter to 4.1u1 while my VUM was still 4.0 (u2 iirc). I decided to upgrade my VUM to match, and all was going well until I got this message:
Error 25085 – Setup failed to register VMware Update Manager extension to VMware vCenter Server
I tried the following KB articles:
Some of them didn’t quite apply because everything was working just fine before the upgrade, but doesn’t hurt to check.
I have two vCenters in linked mode, so I broke the link, still didn’t fix it. During the setup, I would always specify the FQDN to my vCenter, as well as the VUM server to register in vCenter. After I thought I’d tried everything (cleaning registry, checking the ADAM database, etc), I decided to try one last time before opening a case with VMware.
I stepped through everything just the same as before, but when I was at the step of specifying the VUM server to register in vCenter (IP or FQDN), I normally selected the hostname, so I decided to select the IP and everything installed and worked fine.
This may or may not work for any readers, but thought I’d share just in case it helps at least one other person.
I just wanted to add that once VUM was registered in vCenter, I used the vSphere Client to change from IP to Hostname in Network Connectivity section of VUM.