Safe to Power off USB external drive at Logged off status ?

Every once in a while my USB external drive will not allow "Safely Remove Hardware" to complete. It issues the following error / fault ...
Error Header message - Problem Ejecting USB Mass Storage Device, with
the following message - The device 'Generic volume' can not stopped right now. Try stopping the device again later. I have auto-play and Indexing service disabled for this device. It is no big problem, I just terminate power to device after I shut the computer off. Would it be safe to terminate power to device if I logged off of my XP?

 

Hello Dennis,
Try disabling your Antivirus, Antispyware and any other "file monitoring" programs while you disconnect.

 

Dennis L--

If that means you have shut down Windows, the answer is Yes.
I have seen those warnings from time to time. In the back of my mind I seem to remember that after a few seconds there was some indication that it was OK to unplug the USB device after all. (Like a balloon tip in the Notification Area.) But may be I remember wrong.

 

Thanks Mat and Jim

I'm getting suspicious it could be SyncBackSE (paid version). They have frequent updates. It never seems to happen when program/backup profile is run/ended via XP schedule (daily automatics/target internal D drive). But when I run my weekly manual backups (external USB target drive). This latter backup leaves two running processes active. Problem is, manually killing processes does not release ghost hold on external drive. So for now I will just log off and power down external drive. Will post this on SyncBack forum for possible solution/bug.
Thanks guys