1. Preserve the work that is already open
If Photoshop still responds, save your document to a location with enough room before experimenting. Keep your original project, linked assets and recovery information. A scratch-disk warning concerns working storage; it does not make your PSD files or Photos library disposable. Avoid force-quitting an unsaved session just to begin cleanup.
Record the exact message and the operation that triggered it: opening a document, creating a canvas or applying a filter. This helps distinguish ongoing storage pressure from a single unusually demanding operation. Check which drive is full instead of assuming every Photoshop warning refers to Macintosh HD.
2. Inspect the configured scratch disk
In current Photoshop for macOS, choose Photoshop → Settings → Scratch Disks. Older versions call this Preferences. Check which drives are selected and their priority. Scratch space is disk storage used for temporary work; buying more cloud storage does not directly create free space on the selected local drive.
Check that drive’s available capacity in Finder or macOS storage tools. Adobe’s current troubleshooting guidance recommends freeing at least 100GB on the primary scratch disk. Treat that as Adobe’s Photoshop-specific troubleshooting recommendation, not a universal requirement for every Mac app or a promise that every document will fit.
3. Recover space from files you can evaluate
Start with completed exports, obsolete installers or other large files you recognize. If you move a finished project to another drive, open the destination copy and verify its assets before removing the original. Keep a separate backup of irreplaceable work; the new working location alone is not a backup.
Review Trash before emptying it. Moving files to Trash does not recover their occupied space until they are permanently removed. Do not apply Windows instructions for deleting Photoshop Temp files to macOS, and do not remove arbitrary Adobe support or recovery folders while a document is open.
4. Consider another suitable scratch drive
If you already have a suitable drive, Photoshop’s Scratch Disks settings let you select additional drives and change their priority. Adobe lists APFS and Mac OS Extended (Journaled) as supported Mac scratch-drive formats. Verify the drive is connected, writable and has enough capacity before selecting it.
Changing the scratch setting does not move your original document or create a project backup. Do not erase a drive simply to match a suggested format without first preserving its contents. Confirm the selection, restart Photoshop when prompted, and test a copy of a representative document before relying on the new setup.
5. Investigate recurring scratch pressure
Review the document dimensions and units, layer count and recent operation. A mistaken large canvas deserves correction before you start deleting more files. In Photoshop’s performance settings, reducing retained history can reduce temporary-storage demand, but it also reduces the steps you can undo. Make that tradeoff deliberately.
Keep recovery protection unless you understand and accept the loss of recovery opportunities. If Photoshop cannot launch or the warning persists despite adequate space, follow Adobe’s version-specific troubleshooting and contact support with the message, drive and document details. ClearDisk can help locate large local files, but it does not configure Photoshop or repair a damaged project.
References & further reading
These guides combine the linked official guidance with ClearDisk’s documented behavior. Your files and app settings determine the right next step.