Photoshop scratch disk full on macOS Ventura fix

You're in the middle of editing a layered file in Photoshop 2024 on a Mac running Ventura 13.3. You've got 50 GB free on your internal SSD. Suddenly a message pops up: "Scratch disks are full." Photoshop freezes. You can't save your work. You try closing other apps, but nothing changes.

The root cause is simple: Photoshop uses a specific folder on your startup drive for scratch disk space by default. When that folder—Adobe Photoshop Temp—fills up with old, orphaned temp files from crashes or incomplete saves, it triggers the warning. Your actual free space doesn't matter, because Photoshop only looks at that folder's threshold, not the whole drive.

Step-by-step fix

1. Force quit Photoshop if it's frozen. Press Command+Option+Escape, select Photoshop, and click Force Quit. Wait 10 seconds. If it doesn't respond, hold the power button until the Mac shuts down.
2. Restart your Mac. This clears any locked temp files. Hold the power button, choose Restart, or press Command+Control+Power button. Wait for the desktop to fully load.
3. Open Finder and go to the Temp folder. In the menu bar at the top of the screen, click Go > Go to Folder. Type

   /private/var/tmp/

   and hit Return. This is where macOS stores temp files for all apps, including Photoshop.
4. Delete Adobe Photoshop Temp files. Look for folders starting with "Adobe" or "Photoshop" (they're often named something like AdobePhotoshopTemp0001). Drag them to Trash. If you get a permission error, hold Command and click the folder, choose Get Info, unlock the padlock at bottom right with your password, set your user to Read & Write, then try again.
5. Empty Trash. Right-click the Trash icon in the Dock and select Empty Trash. Confirm. This frees up scratch disk space.
6. Open Photoshop and change the scratch disk. Launch Photoshop. Wait for it to load completely. Go to Photoshop > Settings > Scratch Disks (or press Command+K, then click Scratch Disks in the sidebar).
7. Assign an external drive as the primary scratch disk. Uncheck your internal drive (Macintosh HD). Check your external SSD or Thunderbolt drive. If you don't have one, check a second partition or a large USB drive—even a fast SD card works in a pinch. Click OK.
8. Restart Photoshop. You'll see a warning: "Scratch disks have changed. Quit Photoshop?" Click Quit, then reopen Photoshop. The scratch disk should now read 0% used or a very low number.

Still getting the error?

If Photoshop still shows the error after reassigning the scratch disk, check these three things:

1. Your external drive format must be Mac OS Extended (Journaled) or APFS. If it's ExFAT or FAT32, Photoshop won't use it for scratch. You can check in Disk Utility: select the drive, look at the Format field under the name. If it's wrong, you'll need to reformat it, which wipes all data. Back it up first.

2. You might have hidden temp files on your internal drive still. Open Terminal from Applications > Utilities. Type:

sudo rm -rf /private/var/tmp/Adobe*

Press Return, enter your admin password (you won't see characters as you type), press Return again. This wipes all Adobe temp files system-wide.

3. Your scratch disk drive might be failing. Open Disk Utility, select the external drive, click First Aid, then Run. If it finds errors, replace the drive. A failing drive can cause random scratch disk errors even when space seems fine.

One more thing: if you're using the cloud version of Photoshop (Creative Cloud 2024), also clear the cache folder: Go to Library (hold Option while clicking Go in Finder) > Application Support > Adobe > Photoshop 2024 > Adobe Temp. Delete everything in there. This folder is separate from the system temp folder and can fill up fast with synced files.

That's it. You should be back to editing without that annoying freeze. I've had this happen three times on Ventura with different Photoshop versions. The external drive trick saved me every time.