Luminous Landscape Forum
Raw & Post Processing, Printing => Adobe Camera Raw Q&A => Topic started by: julianv on July 12, 2026, 01:55:03 pm
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Adobe says that Photoshop does not support editing of files on attached volumes, such as hard disks and SSDs connected via USB. I am seeing evidence for why they advise this.
Most of my work is on raw files from a Nikon Z8 and iPhone 16 Pro Max. I mostly use Camera Raw 18.4.1.2647, on a Mac Mini M4 Pro, in macOS 26.5.2. No problems with local files. But if I try to edit files on an external SSD (Crucial X9 Pro 2TB), I get frequent kernal panics. I tried the usual recommended workarounds: disabling GPU, flushing cache, etc.
Is this problem present with all external storage devices? Or is it related to latency and speed limits? Can Photoshop and ACR work with faster external devices? If so, what might work? X9 Pro has a USB 3.2 Gen 2 interface, and specs at about 900 MB/s on Blackmagic.
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Adobe says that Photoshop does not support editing of files on attached volumes, such as hard disks and SSDs connected via USB. I am seeing evidence for why they advise this.
They do, where? For decades I've had tens of thousands of documents on external HDs and SSDs connected via USB or otherwise. Never an issue.
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The catalog file can live on an external SSD as well, but it can't live on a network attached volume. Generally though I recommend keeping your catalog on the internal SSD to avoid serious risks of data corruption if the USB cable gets pulled out.
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The catalog file can live on an external SSD as well, but it can't live on a network attached volume. Generally though I recommend keeping your catalog on the internal SSD to avoid serious risks of data corruption if the USB cable gets pulled out.
Agreed. But the OP speaks of Photoshop and editing: "Adobe says that Photoshop does not support editing of files on attached volumes,"
Some files?
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Hah, my bad. Mistakenly thought this was the LR Q&A board since I had been reading that one earlier :-)
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They do, where? For decades I've had tens of thousands of documents on external HDs and SSDs connected via USB or otherwise. Never an issue.
A couple of years ago, I installed a Synology NAS for backups and archives. When I tried editing image files directly off the NAS, I experienced crashes. I contacted Adobe, and was informed that they advised against this. The advisor told me that PS and ACR were only designed and tested for use on local files, because of unpredictable timing issues with external devices.
I thought that maybe I could get away with working off my external SSD, because it is faster than my NAS.
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I thought that maybe I could get away with working off my external SSD, because it is faster than my NAS.
Like many of us, you can.
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Just to be clear, my problem occurs with ACR, not Lightroom. I use Bridge to browse files on the external SSD, double click a preview to open a raw file in ACR, and start editing. I am working in HDR mode, but mostly simple moves: exposure, clarity, cropping, vibrance, etc. The panics occur when I move a slider in ACR.
No problem if I copy the raw files to local storage and work from there.
The issue seems to be something recent, maybe related to the last updates of macOS and PS. I sent crash logs to Apple. Is it worth sending them to Adobe? How?
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I have a M1 IMac and a M4 MacBook Air. I have my LR catalogue and Raw files on a fast external drive SSD. I can then run LR on either. LR is set to backup on exit to a usb stick. I sometimes go from LR to PS using Edit in in LR and then back using Save in PS. I am using the latest versions of LR and PS. So far no problems. Obviously I have several backups of all my images on external SSDs.
Jonathan
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Cut Bridge out of the scenario. Now what happens?
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I edit my raw files on attached SSDs and HDDs all the time from the desktop, from Photo Mechanic and I'm pretty sure through Bridge. No issues I can think of.
My workstation is an M1 Studio and my secondary/field machine an M1 MBP and I can't think of any time I haven't been able to open files through ACR no matter where the files are stored.
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Cut Bridge out of the scenario. Now what happens?
Update: The panics are apparently unrelated to my external SSD, or to Bridge. I tried editing some raw files on my Mac Mini's internal SSD. I double clicked the files in Finder to open them in ACR. Still seeing occasional panics. I don't have a recipe for replicating this - I may be able to edit and save a few files, before I touch a slider and one crashes, after essentially the same moves.
One factor to consider, that probably does not affect most PS/ACR users: I am editing files in HDR mode (the new HDR, not the older compositing workflow). Perhaps there is some flaky stuff in the color management code. I'm going to try changing ACR's color space settings. It was set to rec.2020, 16-bit, which is an odd combo (I don't recall why that was ever set). I will try HDR P3, 32-bit, which is more conventional.
Thanks to everyone, for following my little mystery.
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I'm doing HDR stuff too; there's nothing there that would cause issues with external storage of RAWs.
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I may have found the cause for the kernel panics. When I searched google with the text at the top of the crash dump, I was led to this posting on the Apple forums:
https://discussions.apple.com/thread/256264616?page=2&sortBy=rank (https://discussions.apple.com/thread/256264616?page=2&sortBy=rank)
The screen photo in that post is similar to what I have been seeing, before the system automatically reboots.
The author suggested a workaround: changing refresh rate from ProMotion to 60Hz. I did that, and have not seen a panic since then. So, it appears that, for certain configurations (possibly including Studio Display XDR running with ProMotion) the Adobe/Apple display pipeline is marginally unstable.
I reported the bug to Adobe.