LrC 15.6: JPEG export leaves deleted cr_sdk temp files (~1.8 GB each) held open. 37 GB after a third of a wedding, freed only when quitting. Internal disk fills up.

Given that I wasn’t able to reproduce the leak in temp files when an export finishes, it’s very possible Adobe wouldn’t either. There’s something particular to your configuration we haven’t discovered.

My only suggestion at this point is pretty drastic and time consuming: Make a test catalog using File > Export As Catalog with as many of your photos as reliably triggers the problem. Select the option Export Negative Files so that the original raws are included in the catalog folder.  After verifying the problem reproduces with that test catalog, zip it up and upload the huge .zip file to Wetransfer, Dropbox, Google Drive or similar free service and send me a private message with the sharing link.

If the problem reproduces on my computer, we can get the attention of the Adobe community managers to inject a bug report to the team.

Here’s the logging script I used:

#!/bin/sh

while true; do
    ls junk | wc
    lsof +L1 -p $(pgrep -f "Adobe Lightroom Classic.app/Contents/MacOS/Adobe Lightroom Classic") \
        | grep cr_sdk  | wc
    sleep 10
    done

“junk” is the folder into which the test was exporting the photos.

I reran my test with 3093 raws, all with AI masks, from 8 different cameras from Sony, Canon, and Apple. While the number of open temp files sometimes increased above 5-10 and as high as 23, LR closed them all when the export completed.

I logged the number of photos exported and the number of open temp files every 10 seconds. Examining that data shows that sometimes the number of open temp files explodes for 10 - 30 seconds, but my LR always recovers from that. (Click on a graph to enlarge it.)

This graph shows the number of temp files open versus the number of photos exported so far:

As you’ve observed, for the first 800 photos or so, there’s usually just one file open. But then it gets more ragged, with often 5-10 files open, and at one point 23 files open.

This graph shows the number of open temp files versus time (blue line), and the rate of exports (photos per second) (orange line):

It looks like as the number of open files increases above 5-10, the rate of export slows down quite a bit.

This scatter plot shows the 10-second samples’ rate of export versus the number of open temp files, making the correlation clear:

This is just correlation. But if I were a Camera Raw developer, investigating why the number of temp files sometimes explodes would be a good starting clue as to why there are significant slow downs periodically in the rate of exports. And that might lead to what’s going wrong in your situation.

I reset the preferences as suggested: with Lightroom closed I moved out both files (com.adobe.LightroomClassicCC7.plist and "Lightroom Classic CC 7 Startup Preferences.agprefs"), and Lightroom recreated them on launch.

Then I ran the same export again: same catalog, a full wedding (about 3000 photos, all with AI masks), JPEG to the internal disk, in a single batch. Every 30 seconds I counted the deleted-but-still-open cr_sdk files held by Lightroom (lsof +L1).

• First ~750-800 photos (45 minutes): 2 to 12 files open, released in batches; the minimum stayed between 2 and 5.
• After ~800 photos they stop being released: 11 files, then 20 files totalling 37.1 GB at about 1000 photos.
• Quitting Lightroom raised free space from 81 to 124 GB within seconds.

So with fresh preferences the problem comes back: it starts later, but it reaches the same point as the first time (20 files, about 37 GB). This may explain why it doesn't reproduce with 1000 photos where only some have AI masks: here it starts after about 800 photos, all of them masked.

Photoshop (Beta) was also open during the export; the numbers above count only files held by the Lightroom process.

If useful, the next test is the one with a test catalog on the Desktop.

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If useful, I can run the test with the catalog and export folder on the Desktop.

I think that would be a good test, to see if LR / Camera Raw is getting confused by permissions of the catalog on the external drive or something like that. There have been a few reports over the years of similar things happening. I’m guessing it may not the cause of your problem, but worth a test.

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​@matteoc31415317 all my photos have AI masks applied. 

Just looked at the 1000 in my test, and of what Adobe considers “AI edits”, 383 had AI masks, 75 had AI Remove, 129 had Denoise, 4 and Lens Blur, and 12 had Reflection Removal. 

Thanks to both of you.
1. Earlier versions: same workflow for years, and this never happened before. I've been noticing it for the last few weeks.
2. Formats: I've only tested JPEG export.
3. Export target: internal SSD. The catalog is on an external drive.
4. Frequency: it happened in both exports today. It also happened in the past weeks with another wedding on the same catalog: there the export failed every single time, and the only way through was exporting in smaller batches. Whenever I export a large number of photos the internal disk fills up completely, but it's only temporary files: there is plenty of real free space.
5. Preferences: not reset yet.
One key difference for John: all my photos have AI masks applied. That may explain the ~1.8 GB temp files, which plain raws without masks wouldn't produce. If useful, I can run the test with the catalog and export folder on the Desktop.

​

Hi @matteoc31415317 

Thank you for sharing the detailed information about the issue. To help us investigate the temporary files accumulating during JPEG export in Lightroom Classic 15.6, could you please provide a few additional details?

1. Could you confirm whether the issue occurred in previous versions of Lightroom Classic? If the export worked as expected before, please let us know which version you were using.

2. Does this issue occur only when exporting JPEGs, or have you noticed it with other file formats or export settings as well?

3. Are you exporting the JPEG files to an external drive or your internal SSD?

4. Does the issue occur consistently with every large export, or only occasionally? Have you also tested exporting smaller batches of approximately 50–100 photos?

5. Have you tried resetting Lightroom Classic preferences to check whether the issue persists? If not, please give it a try by following Adobe's instructions: https://adobe.ly/4B79cbO
   
   Please create a backup of your existing preferences before proceeding. If you use the manual reset method, follow the instructions carefully to back up and then rename or move the relevant preferences file to a safe location.

Once you've tried these steps, please share your observations so we can investigate the issue further.

Hi ​@matteoc31415317 

Thank you for sharing the detailed information about the issue. To help us investigate the temporary files accumulating during JPEG export in Lightroom Classic 15.6, could you please provide a few additional details?

1. Could you confirm whether the issue occurred in previous versions of Lightroom Classic? If the export worked as expected before, please let us know which version you were using.

2.  Does this issue occur only when exporting JPEGs, or have you noticed it with other file formats or export settings as well?

3. Are you exporting the JPEG files to an external drive or your internal SSD?

4. Does the issue occur consistently with every large export, or only occasionally? Have you also tested exporting smaller batches of approximately 50–100 photos?

5. Have you tried resetting Lightroom Classic preferences to check whether the issue persists? If not, please give it a try by following Adobe's instructions: https://helpx.adobe.com/lightroom-classic/desktop/introduction-to-lightroom-classic/reset-preferences.html 
   Please use the manual reset method, follow the instructions carefully to back up, and then rename or move the relevant preferences file to a safe location.

Once you've tried these steps, please share your observations so we can investigate the issue further.

I wasn’t able to reproduce this misbehavior on a very similar configuration. My detailed reply suggesting next steps was improperly placed into the moderation queue, so let’s hope it shows up soon.