Userenv errors are profile related.
They generally occur in windows network environments rather than on a standalone system.
Briefly:
Each time you logoff from your user profile or shutdown the system Windows has to save settings to bring them back at next logon. You can see it from the shutdown procedure, a system window says *Saving settings*.
*Saving settings* is basically checking the user section of the registry. Windows checks the registry for modifications, writes the changes and then you're out of the system (*Shutting down*).
This final process must be done when NOTHING from the user is still running on the machine: when something is still running in the background the shutdown process hangs... means user profile files are in use as well as the registry, they cannot be processed for modifications and the session can't be closed.
The weird thing now is you appear to have some backgroung app/service during final system operations: you're not supposed to get to that *Saving settings* stuff if you have other processes running.
The result is your profile do not update correctly for next sessions.
Do you experience any profile settings loss when this happen?
Anyway if you browse through your system services you should notice a third party service running under your user account (not as localsystem or network as the error says), instruct that service to run under system account and you should fix this mess.
