This modification helps identify various logon problems including group policy processing and roaming profile issues. Very helpful but should be enabled for troubleshooting purposes only in verbose mode.

Modify the following registry value:

Subkey:

set this to 0x00030002 –this will give debug/verbose output:

the log can be found at %Systemroot%DebugUserModeUserenv.log  (set the userenv.bak file to read only and it will allow the userenv.log file to grow as needed to capture the logging–don’t forget to undo this step when troubleshooting is done)