Equally annoying -- I've had that problem before, but it was so long ago, I can't remember what the problem was. I have some suggestions. They are admittedly shots-in-the-dark. Some may not even seem logical, based on your symptoms, but it can't hurt to try them. . . Physically disconnect all but one drive. Make that unit "Drive 0", and try booting. (Don't forget to move your terminator over.) If it still gives you the problem, change out the drive select cap, and make it drive 1. Try again. Make sure all of the other drives are powered down and disconnected during the attempt. I seem to remember having either XXDP or RT11 wig-out, because of some quirk with the number of drives attached to the controller, and/or something flaky with the drive select caps. I also had some problem with boot errors when I had two adjacent drives in the rack. It turns out, I had the boot drive positioned half-way out of the rack on the sliders, and it was picking up noise from the drive above or below it.) I'd try "rolling your own" pack with SIMH, and VTServer. Boot XXDP under SIMH using 11/23 emulation with 512K, and make a new XXDP disk on an emulated RL02 pack. Then try transferring it to a blank RL02 with VTServer. NOTE: VTserver will blindly write to the disk, and completely ignores any BAD SECTOR information on the existing pack. So, if you're using a pack with bad spots, it's going to write data over the bad areas, and you'll wind up with an unreliable pack. I hope this helps. . . . T