DavidR
4
Putting it to debug will generate more event viewer entries as you have noticed they are replicated. Me mention of the logging level was in case you had cranked it up, with a view to setting it back.
The only reason there would be a scanning requirement for the C:\WINDOWS\Debug\usermode\userenv.log file is its access and modification (leaving aside the fact that the .log file should be excluded), now that would I assume that you have debug enabled in windows ?
AutoExec.bat isn’t usually used by XP (as you say) so there must be some setting that is trying to access that also.