P: LrC 15.4 & 15.4.1 Cannot create catalog backups directly on SMB NAS shares (backup fails during compression)

Same issue - backups to Synology worked until May, now they don’t.

Greatly appreciated! I am not very well versed in IT so will see if the IT team I use can help me with this. I certainly want a backup that is not only on my one computer. Greatly appreciate this!

​@Sameer K, ​@Rikk Flohr_Photography please merge with this bug report:

https://community.adobe.com/bug-reports-679/lightroom-classic-15-4-1-cannot-create-catalog-backups-directly-on-smb-nas-shares-backup-fails-during-compression-1629454

and move the merged thread into the LR Classic forum (it’s currently in the LR Ecosystem forum).

I have been backing up my LR Classic catalogue to a NAS for years. Since the recent upgrade of LR catalogue it will no longer backup. This started week of 6/15/26

Also happens with an afp share on Mac

Title: Lightroom Classic 15.4.1 cannot create catalog backups directly on SMB NAS shares (backup fails during compression)

Product:
Adobe Lightroom Classic 15.4.1

Platform:
macOS

Summary:
After updating to Lightroom Classic 15.4.1, catalog backups can no longer be created directly on an SMB-mounted NAS share. The backup process fails during the compression stage. Creating the same backup on a local SSD works correctly.

Environment:

• Lightroom Classic 15.4.1

• macOS

• Catalog stored on internal SSD

• Preview files stored locally

• Original photo files stored on NAS

• Backup destination: SMB-mounted NAS share

• NAS accessible and writable from Finder

Steps to Reproduce:

1. Open Lightroom Classic 15.4.1.

2. Use a catalog stored on a local SSD.

3. Configure Catalog Settings > Backups to save backups to an SMB-mounted NAS share.

4. Quit Lightroom and allow the catalog backup to run.

5. Lightroom starts the backup process and reaches the compression stage.

6. Backup fails with the message:

   "Lightroom could not back up the catalog. Check folder permissions and make sure sufficient space is available on both the backup drive and the drive containing the catalog."

Expected Result:

• Lightroom successfully creates a compressed catalog backup (.lrcat.zip) on the NAS share.

Actual Result:

• Backup fails during or immediately after compression.

• No valid .zip backup is created.

• Lightroom reports zero valid backups in Catalog Settings.

• Previously failed backup folders are not recognized as valid backups.

Troubleshooting Performed:

1. Verified sufficient free space on NAS and local SSD.

2. Verified read/write permissions on the NAS share.

3. Lightroom can create folders on the NAS.

4. Lightroom can write files to the NAS.

5. Finder can create, copy, and manage files on the NAS normally.

6. Creating a backup to a local SSD works correctly.

7. Lightroom successfully creates a valid catalog backup ZIP on the local SSD.

8. Manually copying that ZIP file to the NAS works without any issues.

9. After copying the ZIP to the NAS manually, Lightroom immediately recognizes it as a valid backup and displays it correctly in Catalog Settings.

Important Observation:

The problem appears to occur only when Lightroom itself attempts to create the ZIP file directly on the SMB share.

The following workflow succeeds:

• Create backup locally → OK

• Copy resulting ZIP file to NAS → OK

• Lightroom recognizes copied backup on NAS → OK

The following workflow fails:

• Create backup directly on NAS → FAIL

This suggests a problem in Lightroom's backup/compression routine when writing directly to SMB network volumes.

Additional Notes:

The issue started immediately after updating to Lightroom Classic 15.4.1. No changes were made to:

• NAS configuration

• SMB settings

• User permissions

• Folder structure

• macOS settings

The same NAS backup workflow worked correctly before the Lightroom update.

Exact same problem. Have been using a folder on my Synology NAS for years that directly accepts LRcc catalog backups. Updated to 15.4 and got the above error box. (Tons of space available on the NAS.) Tried a new folder on the NAS, checked P&S permissions, nothing worked. 

Used the same hack. Plugged in a 1TB ext. SSD and set that as the destination for the LRcc catalog Bup. Went without a problem. Transferred the folder to the NAS. 

There is a problem with LRcc 15.4 recognizing/accepting catalog zip Bup folders.