Photoshop Scratch Disk Full? How to Fix It

You sit down to edit a session, open Photoshop, and instead of your image you get one of the least welcome messages in a photographer's workflow:

“Could not initialize Photoshop because the scratch disks are full.”

Or maybe Photoshop opens, but later tells you it “could not complete your request because the scratch disks are full.”

The frustrating part is that you may have terabytes of storage sitting on an external drive and still get the error.

The good news: this usually does not mean Photoshop is broken. It means the drive Photoshop is currently using for temporary working space does not have enough room for what Photoshop needs to do.

This guide explains what a scratch disk is, the fastest fixes to try, how to change Photoshop's scratch disk, and how photographers working with large RAW files, layered PSDs, panoramas, composites, and batches can keep the problem from coming back.

What does “scratch disks are full” mean in Photoshop?

A Photoshop scratch disk is storage space Photoshop uses for temporary data while you work. Photoshop uses RAM for active work, but complex edits can require more temporary working space than available memory can provide. Photoshop then uses a drive as additional temporary storage.

Adobe's current documentation describes scratch disks as hard drives or SSDs used for temporary storage and says the “Scratch Disk Full” error occurs when Photoshop runs out of that temporary storage space.

That is why plugging in a large external drive does not automatically solve the problem. Photoshop has to be configured to use an appropriate drive as a scratch disk.

Adobe: Resolve scratch disk full errors in Photoshop

Quick fix: what should I do when Photoshop says scratch disks are full?

If you need to get back to editing quickly, try these in order:

Close Photoshop and other large applications.
Check how much free space remains on the drive Photoshop uses as its scratch disk.
Free substantial storage space on that drive. Adobe currently recommends freeing at least 100 GB on the primary scratch disk when troubleshooting this error.
Empty Trash on Mac or Recycle Bin on Windows after deleting files so the space is actually released.
Restart Photoshop.
If the error returns, select another drive with plenty of free space as an additional scratch disk.

If Photoshop will not launch at all, jump to the section below on changing the scratch disk when Photoshop cannot open.

Solution 1: Free up space on your Mac or Windows system drive

For many photographers, the immediate problem is simply that the internal drive has become too full.

Photography fills storage remarkably quickly. RAW files, Lightroom catalogs and previews, exported JPEGs, Photoshop documents, TIFFs, downloads, video clips, duplicate session folders, and temporary files can quietly consume hundreds of gigabytes.

How to check free storage on a Mac

On current versions of macOS:

Choose the Apple menu → System Settings.
Select General.
Select Storage.
Review the available storage and the categories using space.

Apple's Storage settings can help identify large documents, applications, downloads, and other categories. Apple also notes that moving a file to Trash does not release its storage until you empty the Trash.

Apple: Free up storage space on Mac

How to check free storage on Windows

On Windows 11 or Windows 10:

Open File Explorer.
Select This PC.
Look under Devices and drives to see the available space on your drives.

You can also go to Settings → System → Storage to see what categories are consuming space. Microsoft's Cleanup recommendations and Storage Sense can help identify temporary files, large or unused files, and other items you may choose to remove.

Microsoft: Free up drive space in Windows

What files can photographers move off the internal drive?

Do not start randomly deleting folders because Photoshop is yelling at you.

Instead, look for large files you understand and can safely move or remove. Depending on your workflow, candidates might include completed client-session folders that are already properly backed up, old exports that can be recreated, video files, Downloads, disk images and installers, old device backups, or applications you no longer use.

Do not treat moving files to one external drive as a backup strategy. If the only copy of a client's photographs is on that external drive, you have moved the risk rather than solved it. Maintain an appropriate backup workflow before removing working files from your computer.

For Mac users, Apple specifically suggests that large media files can be moved to another storage device when appropriate. Windows similarly supports moving personal files to external storage to free internal space.

Solution 2: Change Photoshop to use another scratch disk

If you have a fast drive with plenty of free space, you can configure Photoshop to use it as a scratch disk.

Change the scratch disk on a Mac

Open Photoshop.
Go to Photoshop → Settings → Scratch Disks.
Select the drive or drives you want Photoshop to use.
Arrange the drives in the preferred order if needed.
Click OK.
Restart Photoshop.

Change the scratch disk on Windows

Open Photoshop.
Go to Edit → Preferences → Scratch Disks.
Select the drive or drives you want Photoshop to use.
Arrange the priority as needed.
Click OK.
Restart Photoshop.

Adobe recommends prioritizing faster drives and notes that supported scratch-disk formats include APFS and macOS Extended (Journaled) on macOS, and NTFS, exFAT, and FAT32 on Windows.

Adobe: Set up and manage Photoshop scratch disks

Why doesn't my external hard drive fix the scratch disk error?

This is one of the most common points of confusion.

You can have a 2 TB, 4 TB, or larger external drive connected and still receive the error if Photoshop is using your nearly full internal drive as its scratch disk.

The external drive's free space only helps Photoshop's scratch-disk problem if Photoshop is configured to use that drive and the drive is available and suitable for the task.

Also remember that the fastest available drive is generally preferable. A fast SSD used as a scratch disk will typically make more sense for active temporary work than a very slow archival drive, assuming your overall storage and backup strategy supports it.

Solution 3: Remove Photoshop temporary files

Photoshop temporary files can sometimes remain behind, especially after crashes or interrupted sessions.

Adobe's current scratch-disk troubleshooting guidance specifically tells Windows users to look for files beginning with Photoshop Temp on the C: drive as part of troubleshooting.

Before deleting temporary files, close Photoshop completely. Do not delete files you cannot identify simply because they are large.

If you are uncertain about a file, leave it alone and use Adobe's current troubleshooting documentation rather than guessing.

Solution 4: Reduce Photoshop History States

Photoshop's History feature lets you step backward through edits, but those states require resources. Complex work on very large photographs can make the temporary-storage requirement substantial.

Adobe notes that reducing History States can reduce the amount of scratch-disk space Photoshop needs.

To adjust it:

Open Preferences/Settings → Performance.
Find History & Cache.
Reduce the number of History States if your workflow does not require as many.
Restart Photoshop if necessary.

Do not reduce settings merely because a blog post tells you to. Think about how you edit and how far back you realistically need to undo changes.

Adobe: Photoshop performance preferences

What if Photoshop won't open because the scratch disk is full?

If Photoshop cannot get far enough to let you open its normal settings, start by freeing space on the system drive outside Photoshop.

You can also select a scratch disk during launch: hold Command + Option on Mac or Ctrl + Alt on Windows while opening Photoshop, then choose a suitable drive with free space. This selects a scratch disk; it is different from resetting preferences.

Adobe’s performance guide documents the startup scratch-disk shortcut.

Adobe also documents startup troubleshooting and preference-reset options for scratch-disk problems. Resetting Photoshop preferences returns settings to their defaults, so treat that as a troubleshooting step rather than the first button to push.

Adobe's current instructions for resetting preferences during launch are to close Photoshop and then hold Shift + Option + Command on macOS or Shift + Alt + Ctrl on Windows while launching Photoshop, then confirm the reset when prompted.

Because shortcuts and application behavior can change between Photoshop versions, check Adobe's current documentation if the startup process on your version looks different.

How much free space does Photoshop need for a scratch disk?

There is not one fixed number that works for every photographer because scratch usage depends on the documents and operations involved.

A single flattened portrait JPEG is very different from a multi-gigabyte layered PSD containing smart objects, masks, filters, panoramas, or large composites.

For troubleshooting the “scratch disks are full” error, Adobe currently recommends freeing at least 100 GB on the primary scratch disk. Treat that as troubleshooting guidance rather than a promise that every Photoshop workflow will fit inside exactly 100 GB.

Why photographers run into scratch disk problems so often

Photography workflows are unusually good at consuming storage.

A session may begin with hundreds or thousands of RAW files. Then come previews, catalogs, edited masters, PSD or TIFF files, exported JPEGs, album files, video clips, and backup copies. Add several active clients and it becomes easy for an internal SSD that seemed enormous when you bought the computer to fill up.

Large Photoshop operations also matter. Adobe notes that scratch usage depends on how many pixels an operation changes; large image-wide operations require more resources than small edits.

The long-term answer is therefore not just clearing 20 GB every time Photoshop stops working. It is building a storage workflow that anticipates the size of professional photography files.

Keep Photoshop Working Space Separate From Your Photo Archive

Review where your originals, Lightroom catalog, previews, and Photoshop working documents live before moving anything. Free space on an archive drive does not help a different drive selected for Photoshop scratch storage. Keep a record of those locations so a cleanup does not turn into a search for missing files.

Use the photography backup and file workflow guide to plan what stays on the working drive and what can be archived after its backups are verified.

How to prevent “scratch disks are full” from coming back

Keep meaningful free space on your working drive. Do not routinely operate with your internal SSD nearly full.
Review storage before a heavy editing week. Wedding season or a large commercial job is a bad time to discover you have 6 GB remaining.
Archive completed jobs intentionally. Move completed work according to your storage and backup plan rather than letting every session live forever on the internal drive.
Empty Trash or Recycle Bin after intentional cleanup. Deleted files may continue occupying storage until you do.
Configure Photoshop's scratch disks deliberately. If you own an appropriate fast drive with substantial free space, tell Photoshop to use it.
Watch very large PSD and TIFF files. Layered files and complex edits can become enormous.
Maintain backups before cleaning. Never solve a storage warning by creating a client-data disaster.

Scratch disk full on Mac: the short version

If you are a Mac photographer who just wants the checklist:

Quit Photoshop.
Go to Apple menu → System Settings → General → Storage.
Identify large files you can safely move or remove.
Empty Trash after deleting files.
Try Photoshop again.
If needed, open Photoshop → Settings → Scratch Disks and select another suitable drive with plenty of free space.
Restart Photoshop.

Scratch disk full on Windows: the short version

Quit Photoshop.
Open Settings → System → Storage or check free space under This PC.
Use Storage/Cleanup recommendations or manually move files you know are safe to relocate.
Empty Recycle Bin.
Check for abandoned Photoshop Temp files according to Adobe's guidance.
Try Photoshop again.
If needed, open Edit → Preferences → Scratch Disks and choose another suitable drive.
Restart Photoshop.

One storage warning photographers should take seriously

A scratch-disk error is annoying, but it can also be a useful warning that your working storage has become too crowded.

Do not let the urgency of finishing an edit lead you into deleting original photographs, catalogs, or client files without knowing where your backups are.

Fix the immediate Photoshop problem first. Then take a few minutes to look at the larger workflow: where active sessions live, where completed work is archived, what is backed up, and how much free space you normally leave available for editing.

Your computer does not need to be perfectly organized to edit photographs. But Photoshop does need somewhere to work.