I just lost a disk drive and had to reload the entire system. After the operating system reloaded, I used the Restore User Profiles (RSTUSRPRF) and Restore Configuration (RSTCFG) commands from the Save System (SAVSYS) tape. Since my user libraries weren't restored yet, and all my user profiles referenced output queues and other things from those libraries, I couldn't sign on.
IBM software support wouldn't help me since we bought the system from a VAR, so I reloaded the operating system and didn't restore the user profiles until all libraries were restored. I'm sure there were ways around this, but it was 2 a.m. and I was tired. The reload worked and all went fine after that. My advice to everyone is to make sure your backup strategy is complete. You need at least SAVSYS, SAVLIB *IBM, SAVSECDTA, SAVDLO, and SAVLIB *ALLUSR.
And don't restore user profiles until any referenced library or output queues are restored. I hate those gotchas at 2 a.m.!