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Jiemingzhu
Participant
October 22, 2026
Open for Voting

Lightroom Classic 15.6 — Photo uploads permanently stalled while collection synchronization succeeds

Lightroom Classic synchronization has been stalled for an extended period, initially under version 15.5 and continuing under 15.6.

Approximately 1,400 photographs remain pending. Lightroom Classic displays the status "Uploading" with "Image" in the sync details.

Steps to reproduce

  1. Open Lightroom Classic with synchronization enabled.

  2. Observe that existing photograph uploads remain stalled.

  3. Import a new JPEG from local Mac storage, independently of NAS storage.

  4. Create a new collection and enable synchronization.

  5. Add the JPEG to that collection.

  6. Verify that the collection appears in Lightroom Web and Lightroom Mobile.

  7. Observe that the photograph itself never uploads.

Expected result

Both the collection and its photograph should synchronize successfully.

Actual result

The collection synchronizes, but the photograph remains queued. Existing uploads also remain stalled.

Previously, restarting Lightroom Classic advanced synchronization by approximately four photographs before stalling again.

Troubleshooting already completed

  • Confirmed source RAW files are accessible on NAS storage.

  • Confirmed a locally stored JPEG exhibits the same problem.

  • Cleared all Lightroom Web Sync Issues.

  • Verified the problem persists across Lightroom Classic versions.

  • Generated a synchronization diagnostic report on October 22, 2026.

Diagnostic findings

The report includes AuxMissingError, BinaryMissingError, RevisionExistsError, and an HTTP 403 response involving an XMP Develop upload.

The diagnostic snapshot also shows zero scheduled binary uploads despite the unresolved synchronization queue.

Please investigate whether Lightroom Classic's synchronization database or Adobe's cloud asset state has become inconsistent, and provide a supported recovery procedure that preserves the master catalog, local originals, and edits.

Environment

Lightroom Classic 15.6
macOS: [insert exact version from Help → System Info]
Computer: MacBook Pro M4 Max
Catalog: Single Lightroom Classic catalog
Photo storage: TerraMaster NAS and local Mac storage

    1 reply

    CORCTON34033231
    Community Expert
    CORCTON34033231Community Expert
    Community Expert
    October 22, 2026

    Hi Jiemingzhu,

     

    Thanks for the detailed report. Adobe's official Lightroom Classic sync FAQ suggests the following checks when a sync stays stuck for a long time:

     

    1. Click the cloud icon to see the number of syncing images, and review the syncing assets in the Sync Preferences window (Preferences > Lightroom Sync).

    2. In Preferences > Lightroom Sync, use "View Sync Status on Web" to review the sync status on the web.

    3. Check whether an "All Sync Error" collection has been created in your catalog. If it has, open that collection and hover over the images to see the detailed error info for each image.

    4. If there is no All Sync Error collection, no sync issue on the web, and the numbers are still not settling down, the FAQ's next step is to contact Adobe Customer Support.

     

    One caution from the same document: please don't rebuild sync data unless the Adobe team specifically directs you to.

     

    Official doc: Lightroom Classic sync FAQ

    https://helpx.adobe.com/lightroom-classic/desktop/technical-support/workflow-issues/sync-issues/sync-faq.html

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