Acronis Scheduler 2 Causing pauses on USB drives

Acronis True Image Home 2010 on a Windows 7 machine, scheduler causing 6 to 8 second pauses about every minute. If I have multiple USB drives attached it will pause one drive, after that drive resumes operation the next USB drive pauses and so on.

I have tried with and without any scheduled backups, non-stop backup is off. No backups in progress.

If I stop the schedul2.exe task the problem stops as well.

Under normal operation it would probably not even be noticeable, but while watching video from a USB attached drive the video playback is totally hosed.

Is this normal? Are there any settings I can change to have the scheduler ignore USB drives?