Running the update for vCenter Update Manager 5.5 from 5.1 on a WIndows 2008 R2 server after upgrading all the other components I was receiving an error like below and couldn't click next in the installer to get past the credentials page:
validation failed for service account user
setup failed credentials could not be validated
Looking in the install log vminst.log in %temp% showed the following but wasn't particularly useful:
process returned 199
Error:: unknown VC error
To get past this I checked if the service account for VUM can log in to vSphere
client, I couldn't. I then added the service account explicity as an administrator at the vCenter level with inheritance to be able to login to vCenter. I could now validate the credentials for the install and complete it.
