Participant

Photoshop 27.6 & 27.5 Scratch Disk Management Issues on Mac

Forum|Forum|2 days ago
May 13, 2026
3 replies
40 views

Issue Summary: Photoshop 2026 (versions 27.5 and 27.6) misreads available free space on external SSD volumes — showing the SSD's free space as identical to the local drive's, changing the reported value on every launch, which prevents document creation with a "scratch disks are full" error. It causes Photoshop to crash when any tool is used, even after a dedicated partition workaround. The same hardware and configuration work in Photoshop 2025.

Product and version: Adobe Photoshop 2026 — issue reproduced in both 27.6 (latest at time of report) and 27.5.

Operating system: MacBook Air M1, 16 GB macOS Tahoe 26.5

Background: I have been a Photoshop user for 19 years. I had been getting scratch disk problems over time (last 3-4 years, especially), so I purchased a dedicated external SSD and moved all other programs onto it. Under Photoshop 2025, the setup was somewhat working — it functioned when scratch usage stayed around 20–50 GB, but caused issues while editing a single picture for too long. I then updated to Photoshop 2026 (27.6), and the application became unusable as described below.

Steps to reproduce and what happened (full sequence):

Step 1 — Initial attempt: change scratch disk from local drive to SSD.
1. Connect the external SSD, which has 1.83 TB of free space (verified by macOS Finder).
2. Launch Photoshop 2026 (27.6).
3. Open Preferences > Scratch Disks.
4. Uncheck the local drive, check the external SSD.
5. Observe what Photoshop reports for free space on each drive.

What actually happened in Step 1:Photoshop displayed the SSD's free space as equal to the local drive's free space, even though the SSD has 1.83 TB free and the local drive does not. The reported value was not just wrong once — it was always read as equal to the local drive, and the displayed number changed every time Photoshop was launched. When I tried to create a new document, Photoshop refused with the error "scratch disks are full," so no document could be created at all.

Step 2 — Workaround attempt: create a dedicated APFS partition.
1. Using Disk Utility, create a dedicated 500 GB APFS partition on the SSD.
2. In Photoshop 2026, set the new partition as the only scratch disk.
3. Restart Photoshop and observe how the partition is reported.
4. Launch a second time and observe again.
5. Create a document of 800 × 800 pixels.
6. Attempt to use any tool.

What actually happened in Step 2: On first launch after creating the partition, Photoshop correctly read it as 500 GB free. On the second launch, with no files written to the partition and no other changes to the system, the reported free space dropped to 464 GB. With the partition selected as the scratch disk, Photoshop did allow me to create a small document (800 × 800 pixels). However, the moment I tried to use any tool, Photoshop said, “scratch disks are full”.

Step 3 — Official troubleshooting guide.
I followed every step in Adobe's official guide for scratch disk full errors: https://helpx.adobe.com/photoshop/desktop/troubleshoot/performance-stability-issues/troubleshoot-scratch-disk-full-errors-in-photoshop.html

What actually happened in Step 3:None of the recommended steps resolved the issue. The misread free space, the false "scratch disks are full" error, and the crashes on tool use all continued.

Step 4 — Downgrade to Photoshop 2026 (27.5).
Via Creative Cloud > Other Versions, installed Photoshop 2026 version 27.5 and repeated the same scratch disk configuration.

What actually happened in Step 4:** Exactly the same behaviour as 27.6. The version change made no difference.

Step 5 — Control test: Photoshop 2025 (26.11.4).
Installed Photoshop 2025 (version 26.11.4) via Creative Cloud, with the same SSD, the same partition, and the same scratch disk configuration in preferences.

What actually happened in Step 5: Photoshop 2025 reads the SSD's free space correctly, lets me create documents, and allows tools to function. This isolates the bug to Photoshop 2026's scratch disk/volume free-space handling. Note that it even worked with local space, which was far more minimal.

Expected result across all steps: Photoshop 2026 should correctly read the free space on the external SSD (1.83 TB free) and on the dedicated 500 GB APFS partition, allow documents to be created at any size, and let tools function normally with hundreds of GB to terabytes of scratch space available.

Actual result summary:
- SSD free space is misread as equal to the local drive's free space, with the value changing every launch.
- Without a partition workaround: no document can be created at all ("scratch disks are full").
- With a 500 GB partition: a small document can be created, but Photoshop crashes the moment any tool is used. Reported partition free space drops from 500 GB to 464 GB on the second launch with nothing written to it.
- Bug present in both 27.6 and 27.5.
- Bug not present in Photoshop 26.11.4 on the same machine and configuration.

Additional verification performed:
- Confirmed partition format is standard APFS (not case-sensitive).
- Confirmed macOS Finder reports correct free space: 1.83 TB on the SSD as a whole, ~500 GB on the partition.
- Confirmed write access.
- Reset Photoshop preferences via Cmd+Option+Shift on launch.
- Tested with the partition as both the sole scratch disk and the priority-1 scratch disk.

I am 28 years old, and I have been using Photoshop since I was 9. That is 19 years — most of my life. It is not just software I use for work; it is a tool I grew up with. I am writing this because I genuinely want it fixed, not to complain. If there is anything specific your team needs from me to reproduce the issue, I am happy to provide it.

jinxcroftAuthor

Participant

Thank you so much for taking the time to read through all of that and for the thoughtful suggestions. I really appreciate it!

To answer your questions:

1. Administration privileges look fine on my end.
2. The drive naming idea — I'm not 100% sure, I'll have a look at that. Maybe the new section might not look like ‘removable’.
3. As for the internal drive space, I'm currently using 227.54 GB out of 245.11 GB, so yes, that's very likely a factor. I did my best to clean it, and ended up with this result.

Unfortunately, I don't have screenshots to share. I kept trying different versions in the meantime, and as I mentioned earlier, another version of Photoshop is actually working correctly, so the issue seems to be specific to this version rather than the hardware setup.

J E L

Community Expert

You’re welcome, @jinxcroft! I think you are very short on free scratch space internally, and that could be adding to the problem, even with the larger external drive. But I’m glad to hear that rolling back to an earlier version is working. Can you tell us which version is working, so others might have that info, if needed? And thanks for coming back on to let us know you found a temporary solution. Please keep us updated here if anything else comes up!

jinxcroftAuthor

Participant

26.11.4 (2025) release seems perfectly fine! I definitely will. Thank you for your time and support.

AnnaAnPhoto

Participant

I am experiencing another issue with Photoshop 2025 on macOS.

A DNG file generated through Lightroom Super Resolution cannot be opened in Photoshop.

Error message:
“The file-format module cannot parse the file.”

The same file still opens normally in Lightroom, so the DNG itself does not appear to be completely corrupted.

Workflow:
Canon R5 CR3 → Lightroom Super Resolution → DNG → Photoshop 2025 fails to open

This looks like a Camera Raw / file parsing issue between Lightroom and Photoshop.

Has anyone else experienced this?

J E L

Community Expert

@AnnaAnPhoto, you have a separate issue from @jinxcroft. Can you please start a new topic post and restate your issue? Here’s the link to do it: https://community.adobe.com/topic/new

J E L

Community Expert

Hi @jinxcroft, it’s been a while since you posted without any replies; so sorry about that. I read everything carefully and really appreciate and admire how much time you spent documenting what’s happening. I am not sure why this is happening. It seems you’ve checked just about everything. Are you sure you are running Photoshop with administrator privileges? Look under Apple Menu > System Settings > Users & Groups.

The only other thing I can think of, which I’m sure is obvious to you, is renaming the external drive to a unique name, especially without "removable," in case it would be misidentified. Maybe there is a label somewhere you aren’t seeing or detecting? I mean, the drive is showing up, but why is it reading the wrong free space? Any screenshots you can share?

Finally, even on startup, Photoshop reserves scratch space to ensure smooth operation. I believe the recommendation is to keep at least 20–25% of your scratch disk free. Do you have that much free space on your internal drive?

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