My MicroVAX went from booting from DUA0 one day to acting as though the drive does not exist the next.Error code is:?41 DEVASSIGN, DUA0 ?06 HLT INST ?PC = 00000C1A. ? The tape unit seems to be OK, but I don't have a bootable tape to try it with. ?I bought another KFQSA board hoping it would help but it did not. The two drives seem to be spinning, but I don't know their condition. I hope you will take the time to think about what might be wrong. I have been working with Dan Snyder in PA, and he said to try e-mailing your group. Thanking you in advance, Wayne Verish