This is most commonly due to installing Photoshop CS/CS2 <i>before</i> doing an archive and install of Mac OS10.3 or OS10.4.<br /><br />One solution is to reinstall Photoshop 7/CS/CS3 after you have installed Mac OS10.3 or OS 10.4.<br /><br />If you have Photoshop 7 and 8(CS), the easiest way to reinstall Photoshop (without disturbing the original installation) is to install to your desktop. After the install is done just trash the Photoshop folder on the desktop.<br />Note: This will only work with Photoshop 7 and 8(CS) but not with 9 (CS2).<br /><br />Photoshop CS2 you must delete the Photoshop CS2 folder. If you have any 3rd party Plugins or presets remove them from the folder before deleting. Just placing the folder in the trash will not work it must be deleted. After reinstalling CS2 you can now put all 3rd party Plugins and presets back in the new folder.<br /><br />---------------------------<br />Another solution courtesy Anne Shelbourne<br /><br />Open your Previous System folder. <br />Find "Adobe Unit Types". <br />Copy it into: <Your current system Hard Drive>/Library/ScriptingAdditions/<br />Then reboot your Mac.<br /><br />---------------------------<br />However, if you happen to be running a non-English version, like Photoshop CS CE or Photoshop CS ME, it appears the missing file does not get installed. You would need to install and delete the international English version first.