Fixing the Photoshop CS4 “One or more files in the Adobe Application…” Error (updated)

For some reason this error has crept up on several of my machines recently when starting Adobe Photoshop CS 4 on the Mac:

“One or more files in the Adobe Application Support folder, necessary for running Photoshop, are missing. Please run the Photoshop installer and re-install Photoshop.”

Surprisingly, the solution was both quite simple and posted on Adobe’s website:

Solution 1: Copy the Adobe Unit Types file to Library/ScriptingAdditions.

Copy the Adobe Unit Types file in the Previous System folder to /Library/ScriptingAdditions.

Solution 2: Create a new ScriptingAdditions folder, and then reinstall Photoshop.

Create a new folder in /Library and name it ScriptingAdditions.
Remove and reinstall Photoshop.

Solution 3: Make sure there is not a space in the ScriptingAdditions folder name.

On two of my Snow Leopard machines, the ScriptingAdditions folder was missing.  I restored from another computer and the error was gone.  On my third machine, the file and folder were there, but the Adobe Unit Types file was created in 2005.  After replacing with a more recent copy, I was back in business.

Update 02.03.10: Adobe has posted a new 64bit clean version of Adobe Unit Types.osax (version 2.1.0) in a TechNote titled “Error about unit type conversion occurs when running an AppleScript in Photoshop (Mac OS X 10.6).”  This updated version works great for me on 10.6.2.