After getting a new desktop recently, I opted to install Windows 7 64-bit and haven’t looked back. Adobe Photoshop CS4 runs great in 64-bit, although I have a few plugins that aren’t 64-bit compatible.
So while I can launch Photoshop’s 32-bit instance, the Lightroom always launches the 64-bit version when you use the built-in “Edit with…” functionality. I was tearing my hair out trying to figure out how to get Lightroom to use the 32-bit instance of Photoshop instead. Hallelujah, I finally found a solution!
The solution requires a change to the Windows Registry. There is an unrelated Adobe’s Knowledge Base article that gives the location of the Photoshop registry keys, I was able to figure out how to get this to work finally.
Warning: Backup your registry before attempting this fix.
1. Open the Windows Registry editor by hitting <Windows Key>+R to bring up the Run box, and type in regedit.
2. Find the following registry key:
3. There are 2 keys present with the following values (assuming you installed Photoshop to the default location):
(Default) C:\Program Files\Adobe\Adobe Photoshop CS4\Photoshop.exe
(Path) C:\Program Files\Adobe\Adobe Photoshop CS4\
4. We need to just change the path to the 32-bit version of Photoshop instead. Double click on each one, and change the values to the following:
(Default) C:\Program Files (x86)\Adobe\Adobe Photoshop CS4\Photoshop.exe
(Path) C:\Program Files (x86)\Adobe\Adobe Photoshop CS4
Now when you’re back in Lightroom, you should be able to use the “Edit in Photoshop” functionality and it will launch the 32-bit version of Photoshop.