If you use Photoshop CS and have recently upgraded to Tiger via Archive and Install, you may have noticed that you can’t drag and drop files or double-click on them from the Finder to open them. The only way to open the files is via the File Browser or the Open dialog box. Needless to say, this is very annoying.
The problem is linked to the Archive and Install feature of the Mac OS X installation process. To restore the functionality, you’ll need to reinstall Photoshop CS. I don’t know if this problem is duplicated with Photoshop CS2.
I looked everywhere for a solution to this problem before finding the answer on Macintouch’s Tiger Reports pages. I didn’t enter the right Google search terms to find this answer apparently. “Tiger Photoshop CS Drag and Drop” brings up the listing quickly but not “Photoshop Drag and Drop Problem Open Mac OS X”.
tow.com 
this is happening to me with 10.3.9. it is annoying indeed!
this is happening to me with 10.3.9. it is annoying indeed!
It can be fixed without a re-install! Go to your /Previous System/Library/ScriptingAdditions/ folder and copy the file “Adobe Unit Types” to /Library/ScriptingAdditions/ on your new system. (you may need to create the folder.)
I might work (and save you later headaches) to move it to ~/Library/ScriptingAdditions/, but I haven’t tried it.
Jeffrey:
Thanks for the tip! That solved the problem without having to re-install PS!
-adam