[BillArnette]

I don't think its the backup program. I seem to be able to run my batch file from the command prompt anytime. It's only if it runs from the task scheduler that it fails.

Update: It is definitely an issue where another build is running as a different user at the same time as my build; both started by task manager. His build is hanging in a script step which keeps VisBuildCmd.exe running forever. When my build tries to run it fails with the 'class not registered' error.

However, as it has always done, it still runs if I run my batch file explicitly from the command line; even if his build is hung. Maybe because the cmd.exe is the parent proces s instead of mstask.exe?

Interestingly, if I run his build as me and then run my build, it works.