- Drive not terminated properly.- Possible directory corruption. Check the drive with Norton Disk Doctor, Disk First Aid, MacCheck, etc. Reformat if needed.- Incompatible formatter (e.g. older versions of Disk Manager Mac or SCSI Director). Hard Disk Toolkit should be used on PT|24 systems.- One user reported that this was caused by the Sound Manager installed by OS 7.6.1. Reverting back to the Sound Manager form 7.6 fixed the problem.