Unarc OS 3.9

[Matt_H]

It's very likely that some of your files in SYS:Classes have been accidentally deleted or replaced with older versions (badly written installer scripts are usually to blame - they don't check versions before overwriting).

You can pull them off the 3.9 CD (or Boing Bag?) to recover.

[Matt_H]

I can't perform a re-installation of OS3.9 as i would lose 3gb of data on my hd!

Yes you can. AmigaOS doesn't purge your hard drive when you reinstall but do a backup to be safe (especially of your startup-sequence and user-startup files).

But you shouldn't need to reinstall. SYS:Classes is a directory. The files in it have been overwritten with older, incompatible versions. Copy the originals from the equivalent directory on the CD. I think the BoingBags updated them further, so run those installations to be on the safe side (there are ways to do it manually, but the installer is easier).