Did You resolve this issue?
I have got the same problem after upgrade vcenter server appliance from 5.1.0a to 5.1.0b.
If "use windows session credentials" checkbox is check, then I've got error: "General system error occurred: Cannot get user info" but if i put credentials manually then I can login without anny issues.
My vSphere Client OS is Windows 8 Ent and user have local administrator rights. My AD forest and domain level is 2012 but with the same AD on earlier version of VCSA i don't have any problem with login using Windows session credentials.
