The Finder in many versions of Mac OS X will do strange things if you don’t include all icon resources. Make sure that you fill in the entire grid when working with IconBuilder (create 16×16, 32×32 and 128×128 resource sizes.)
Another thing to watch out for is the Finder caching older versions of the icon. It doesn’t always show the most recent version you’ve applied. To work around the caching bug you should try logging out and back in again.
If you find that you need to do this often, you can add a “Quit” item to the Finder’s menu. Quitting and restarting the Finder will refresh the cache without the need to logout. You can add “Quit” to the Finder using a free tool called TinkerTool.
Finally, it’s not always enough to restart the Finder. If you find that the problems persist, you’ll need to reboot.
IconBuilder writes files in a way that will cause the Finder to update its cache, but there can still be problems if an icon is been applied to a folder or disk.
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