Based on your description, there doesn’t seem to be anything wrong.
You shouldn’t ever see the Photoshop scratch files. They’re invisible cache files.
macOS works the same way…your Mac creates virtual memory swap files, a huge “sleepimage” cache, storage snapshots, and many other large temporary files that you never see and can’t find because even though they’re temporary and take up a lot of space, they’re set to be hidden. Even their folders and subfolders are hidden from the user, unless you know how to reveal hidden system files.
On a Mac, the way to watch the Photoshop scratch disk setting affect free space is to leave a Finder desktop window open viewing the scratch disk volume (or any folder on it) with the Status Bar visible, and leave a little space under the Photoshop window to see that Status Bar at the bottom of the Finder window. If the window isn’t showing the Status Bar, choose the command View > Show Status Bar.
Now switch to Photoshop and watch the Status Bar as you work in Photoshop. Over time, as Photoshop loads the scratch disk, the amount of free space shown in the Status Bar will go down. When you quit Photoshop, the amount of free space will jump back up as Photoshop dumps its caches on the way out.
In the demo below, my laptop starts with about 150GB free space, but as I open a large document and start editing, you can see free space keep dropping down to 130GB and finally bottoms out at 128.92GB. After that I close the document, and when I quit Photoshop the free space jumps back up to around 150GB…totally as expected. I don’t think 150GB is a lot of space for a scratch disk, so like you, I plug in an empty external SSD when I’ll be opening a very large file in Photoshop. Using the technique below, I’ve learned that my very large files can temporarily use around 300-600GB of space on the external scratch disk. But simple files don’t need very much; for those, the 150-200GB I keep free on my MacBook Pro internal storage is fine.
If you want to find the actual hidden location of the Photoshop scratch file, it helps to be a little technical. I used a free app called Sloth that lists all open files on the Mac. It showed me that when my external primary scratch SSD is not connected, Photoshop sets up the scratch file on my boot volume, somewhere in
/private/var/folders/…/TemporaryItems/Adobe Photoshop 2025/Photoshop Temp…
Of course, you can’t normally navigate there because it’s a hidden file. Also, the reason I inserted ellipses (…) into the path is because there was a portion of the path that looks like randomly generated letters and numbers so it’s probably different on every Mac, there’s no point in me posting it. And the … at the end of the path is because the numbers after “Photoshop Temp” definitely change for each session, as D Fosse showed.
When my external scratch SSD is connected, the path is:
/Volumes/[name of external SSD]/.TemporaryItems/folders.501/TemporaryItems/Adobe Photoshop 2025/Photoshop Temp…
But even if you show hidden files, when I tried to double-click my way into .TemporaryItems, macOS told me…
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