I like to keep my applications organized by type (e.g., Internet, Security, Entertainment, Multimedia, etc.) in sub-directories of the "Applications" directory. I hadn't tried out iSync 2.0 on Tiger until I picked up a Zire 31 on clearance (great deal -- $99).
I installed Palm Desktop 4.2.1 and the associated Hotsync application, and all seemed to work until I wanted to configure iSync to sync iCal and Address Book with the Palm. Every time I started iSync, it would bounce in the dock for a few seconds and then close, giving the standard "application quit unexepctedly" error. After trying everything I could think of short of reinstalling Tiger, I remembered that I once had an issue back in Jaguar with an application's location on my hard drive. I had moved iSync to an "Apps & Tools" directory within "Applications," so I dragged it up to the root of "Applications" and double-clicked. Lo and behold, it worked! If I drag iSync to any other directory it fails to launch. Apparently not all Mac apps are as 'portable' as I tell my Mac envious Windows-user-friends.
[robg adds: We've covered issues like this here before, but the release of 10.4 seems a good time to reinforce the mesage: for best results, do not move Apple's applications to new homes. I know this is completely against "the Mac way," and it's one of the things about OS X that bugs me, but really, things just work better if you let them be. If it really bothers you, you can use symbolic links and invisible file settings to make it seem as though things have moved around (a hint explaining how to do just that will be upcoming sometime soon).]

