I recently upgraded the main internal hard drive in my PowerBook G3 from the 10 gig up to an IBM 30 gig. To move my data over, I connected via a portable external USB drive case and formatted the new drive. Then I used psyncx to "backup" all my data onto the new drive (retaining the permissions information). I then swapped drives and booted the computer with only one slight problem, my icon positions were all forgotten. A little bit of Command-J later, and no big deal.
After running for several days though, I had installed some applications for work. When I tried to assign these new applications as the default "Open With:" application, the menu said "Not Applicable." I could not figure out why and nowhere is it mentioned on the web (that I could find after three days of searching). Also, all Open With applications defaulted back to the OS X presets (PDF files opening with Preview instead of Acrobat, that kind of thing). When I tried to change it ... same error "Not Applicable."
Finally, I decided that since this was a type/creator problem, I would harken back to my OS 9 days. The good ol' days when everything could be sorted with a desktop rebuild. Low and behold, when I booted into 9 (not Classic), I noticed that most of the icons had gone generic, a sure sign of Desktop Database corruption. I rebuilt the desktop and booted back into X. I was greeted by files that could be assigned to any program on my hard drive with no problem.
So far, the IBM drive seems to be working well (it's speedy, but only 4200rpm). The only thing seems to be that it is a bit louder than the original drive which will very soon be available on E-bay.
[robg adds: Clearly, this problem should be solvable within OS X, as many machines now won't boot into OS 9 at all. However, in searching the web and Apple's KnowledgeBase, I couldn't find a simple solution. Ideas, anyone? I'll modify the hint if someone comes up with a functional OS X solution.]

