OK, I'll see...
Compatibility between ZIP disks and some older Macs (notably the Mac Plus) is a bit inconsistent I've read, especially with newer drivers. An unfortunate problem, however, is that if any newer versions of the ZIP drivers which are known to be incompatible are installed on a computer and you put the ZIP disk in it, the disks old, compatible drivers will be invisibly overwritten, rendering the disk unusable on those machines with which it was compatible with previously.
A solution I came up with was to just eliminate the driver altogether and replace it with one which is known to be compatible across a wide range of machines. It just so happens that Apple's HD SC Setup drivers work perfectly for this task. It has to be the patched version, though, because it won't recognize the ZIP disk otherwise.
The fascinating part is that AHDSCS sees it as any other hard disk, and formats it accordingly. It's quick (relatively) and simple.
So now I can move the disk to any computer I wish, and I don't have to worry about the ZIP drivers ruining it (some drivers are still needed for the computer to use the drive, though). Another interesting side effect of this is that the Mac no longer sees it as a removable drive; it treats it as a fixed disk. This means that the Mac doesn't try to eject the disk when it shuts down.
I did this all with ZIP 100 disks, but it seems to work with ZIP 250's too.
Feel free to contact me if you need help.
c