Fix Photoshop Scratch Disk Full Without Deleting Files

The "scratch disk full" error in Adobe Photoshop occurs when the program runs out of designated temporary workspace to perform tasks. While many users assume they must delete personal files or clear their primary hard drive to resolve this, the issue can often be fixed entirely within Photoshop or by managing application-specific cache files. This guide details direct troubleshooting steps to resolve the scratch disk error by reallocating resources, adjusting internal preferences, and purging cached data without touching your primary system storage.

1. Purge Photoshop’s Internal Memory

Photoshop stores undo history, clipboard data, and cache files in temporary memory, rapidly bloating the scratch disk. You can clear this workspace immediately from within the software:

  • Go to Edit (Windows) or Photoshop (macOS) in the top menu.
  • Hover over Purge.
  • Select All.

Note: This clears your current undo history and clipboard contents, freeing up disk space assigned to Photoshop instantly.

2. Change or Add a Secondary Scratch Disk

If your primary drive has insufficient temporary overhead, you can reassign the scratch disk to another partition or a fast external SSD without deleting data:

  • Open Photoshop and navigate to Edit > Preferences > Scratch Disks (Windows) or Photoshop > Settings (or Preferences) > Scratch Disks (macOS).
  • If Photoshop won't open normally, hold down Ctrl + Alt (Windows) or Cmd + Option (macOS) immediately upon clicking the application icon to launch the Scratch Disks Manager.
  • Check the box next to an alternate internal drive, external hard drive, or secondary partition.
  • Use the arrow keys to adjust the drive priority, placing the drive with the most free space at the top.
  • Click OK and restart Photoshop.

3. Manually Delete Hidden Photoshop Temp Files

When Photoshop crashes or closes improperly, it often fails to delete large temporary files. These remain locked on the drive, invisible to standard cleanup tools:

  • Close Photoshop.
  • On Windows, press Windows Key + R, type %temp%, and hit Enter. Look for files beginning with Photoshop Temp or ~PST and delete them.
  • On macOS, open Terminal, type open $TMPDIR, and press Enter. Locate the temporary items folder and remove any lingering Photoshop temporary files.
  • Empty the Recycle Bin or Trash to finalize the clearance.

4. Optimize RAM Allocation

Insufficient RAM allocation forces Photoshop to rely heavily on the scratch disk as virtual memory. Increasing the memory allowance prevents excessive disk usage:

  • Navigate to Preferences > Performance.
  • Under Memory Usage, locate the Let Photoshop Use slider.
  • Increase the value to 75% – 85%. Avoid setting it to 100%, as the operating system requires memory to remain stable.
  • Under the same menu, lower the History States from 50 to a smaller number (e.g., 20) to reduce how many states Photoshop saves to the disk.

5. Disable Automatically Save Recovery Information

Auto-recovery periodically writes your current workspace to the scratch disk. If you are working with large documents, this creates substantial temporary files:

  • Go to Preferences > File Handling.
  • Uncheck Automatically Save Recovery Information Every [X Minutes], or increase the time interval significantly.

6. Reset Photoshop Preferences

Corrupted preferences files can falsely report that a drive is full, even when ample space exists:

  • Close Photoshop.
  • Relaunch the application while immediately holding down Ctrl + Alt + Shift (Windows) or Cmd + Option + Shift (macOS).
  • Click Yes when prompted to delete the Adobe Photoshop Settings file.