Problems with Exporting JPGs

Hello,

I am experiencing a persistent and reproducible problem when trying to export or convert photos from my Lightroom cloud library, and I would appreciate your help investigating it.

Summary of the issue

When I select a large batch of photos (several hundred to several thousand) and run "Export Originals," the process regularly stalls partway through — sometimes after only a few dozen images, sometimes after several hundred. The progress indicator simply stops advancing, with no error message and no further disk or network activity after a short time.

The problem is specific to JPEG-sourced images. RAW files export without any issues, both with and without GPU acceleration enabled. It is not limited to a handful of individual files — it recurs across entire series of JPEGs (in my case, digitized scans from negatives and slides, all processed the same way), which rules out isolated file corruption as the cause.

I have also tried "Render to DNG" as a workaround, since DNG output does not appear to be affected by the same issue. However, this too has now started stalling, specifically during the "Preparing to Render to DNG" phase, before any actual rendering begins.

What sometimes helps (temporarily)

Manually opening one of the images that the export/render process appears to be stuck on, in full-size Detail view, sometimes causes the batch process to resume for a short while before stalling again on a later image. This is not a practical workaround at the scale of thousands of images, but it does suggest the issue is related to how the app fetches or renders full-resolution image data in the background during batch operations, rather than to any single damaged file.

If I cancel a stalled export, Lightroom reports "The file appears to be unsupported or damaged" for the files that were still queued at the time of cancellation. I do not believe this message reflects the actual condition of those files — it appears to be a generic result of interrupting the export mid-queue, since the same files display and open normally elsewhere in the app.

Troubleshooting already performed

• Updated Lightroom to the latest version (Creative Cloud auto-updates are enabled, so the app is always current)
• Updated AMD graphics drivers to the latest version, then restarted the computer
• Tested with "Use Graphics Processor" set to both Auto and Off — no difference in behavior
• Reset Lightroom preferences (renamed the .agprefs file to force a fresh one) — no difference
• Checked Windows Event Viewer (Application log) around the time of the hangs — no relevant errors or warnings logged by Lightroom
• Ran chkdsk on all relevant drives — no disk errors found
• Confirmed via the sync/activity panel that the source photos are fully "Synced and Backed Up" in the cloud, so this does not appear to be a sync-completeness issue on the affected assets

Additional related issue

Separately, I have noticed that the "Local Storage" location I configure in Preferences (moved from the default location to a secondary internal drive) periodically reverts back to the default drive on its own, without any action on my part. I have to re-set it after this happens. I am not certain whether this is related to the export/render hangs, but wanted to mention it in case it is relevant.

System information

• OS: Windows
• Graphics: AMD Radeon 780M (integrated)
• Library size: approximately 75,000+ photos, cloud-based (Lightroom, not Classic)
• Affected content: JPEG images, largely digitized scans from negatives and slides, imported and edited over an extended period without prior issues

Request

Could you please help identify why batch export/render operations stall specifically on JPEG-sourced assets, and why this happens consistently across otherwise unremarkable files? I am happy to provide asset IDs, additional logs, or reproduce the issue with specific instructions if that would help your investigation.

Best regards, Per