Norton Utilities 4.0 - Win95/98
Error: "Unable to operate on drive X: because it is in use by unknown disk utility" when Running Norton Utilities Module
Norton Disk Doctor, Image, Rescue or Speed Disk display the message "Unable to operate on drive C: because it is in use by Unknown disk utility."
One of the hard drives may be compressed with DriveSpace 3, and System Doctor is running.
This seems to occur most often when you run Norton Disk Doctor, Image, Rescue or Speed Disk on a compressed hard drive while Norton System Doctor is also running. To avoid this error, close the Norton System Doctor before running one of these utilities.
If you do not have a compressed drive, close any programs running in the background before running the utility that displays this message.
If the problem is not resolved, the cause might be file corruption on the drive. Run Norton Disk Doctor or ScanDisk to correct the problem.