I've struggled with getting my Mac Plus to boot with its "funny" SCSI over an external for a while, and I finally broke down and bought a 20SC. At least the Plus sees the 20SC, which is a good start. When I first booted the computer(using a System 6 "utilities" disk) with the 20SC connected, I was prompted to initialize the HDD. There were no errors and it reported successful initialization, but the drive doesn't seem to mount. Disk First Aid will see the disk and find no errors, while HD20SC set-up crashes when I try to launch it. Every time I reboot the computer, it reports that there are repairable errors on the HDD and will report successfully repairing them, but it still doesn't mount. The seller had tried the disk with a couple of newer Macs and reported that the drive mounted but was unable to get it to format or to copy files to/from it. Can I guess-based on all of this-that the drive is on the way out? If so, I have a couple of 320mb Apple OEM disks that I know will work-should these work as replacements in the 20SC case?