I have recently purchased two Jaz2 drives for my company. They seem to freeze when coping a 2G Jaz disk to the server or even the resident HD, but 1G Jaz disks work just fine. I've tried hooking them up to different configurations and SCSI cards but still no luck. Any ideas?

Two things can be wrong (perhaps more, but these are the two things that happened to me). The drive is bad (disks may be bad but I hear the drives fail more often) or you have an extension conflict.
Are you running SpeedDoubler? If you are, you need to isolate conflicting extensions. I had the same problem on an older mac (pmac 9600). It turned out that there was a conflict of somesort between some of the new Quicktime 4.0 components and some legacy communication extensions installed by VersaTermPro. Together they would cause SpeedDoubler to lock up on large copies (>1GB transfers).
Try running your copy method with extensions off and see if it locks up. IF it does lock up with extensions off, call the vendor of the drives. You should have 30 days to return by law, after that they will want you to send it back to them (or IOmega Corp.) for repair. In my case the drive went back to APS and they fixed it within a week...no problems since. Since you can use the 1GB disks, it may not be your drive, but a conflict.

hope that helps

If it is extension conflict try disable Norton SharedLib... I have problems recently when NortonShared Lib from Norton Utils 5 is in extensions folder...

Hope this helps

I've had the same crisis ever since I switched to a G4/OS9. I suspected it was the Jazz Jet card in my case.

Frustrated, I formatted the 2g puck with SoftRAID's utility to cure my woes. This is not a recommended fix by Iomega.

I posted all over and never found an answer in the groups.