@eXidy
Sounds like a disk drive that does not work 100%. Take the drive out of your A600 and install using that drive. We also sell new drives if you need one - have several. Also the only way to verify a disk is to read it from track 0 to 79 - using tools such as transadf. My guess your A4000 drive needs alignment/cleaning - that service we offer also.
amigaATnishtekDOTcom
