[Immich] HEIC thumbnails are not generated on v2.7.5, while original files open normally

[sykim4468]

Description

After updating the Home Assistant Immich add-on to v2.7.5, thumbnails for .HEIC / .heic photos are not being generated.

The original HEIC photos open normally when clicked, but the timeline shows image loading errors because the thumbnails are missing.

This appears to affect HEIC files broadly, not just a few individual files.

Important comparison

I tested the same HEIC files on another Immich instance running v2.4.1, and thumbnails are generated and displayed normally there.

So the HEIC source files themselves do not appear to be corrupted.

Current environment

• Home Assistant OS
• Immich add-on by alexbelgium
• Immich version: v2.7.5
• External media path mounted under:
  /media/IMMICH/photos/...

What works

• Original HEIC files open normally
• Thumbnail generation jobs are queued and processed
• Other non-HEIC media appears to load normally

What does not work

• HEIC thumbnails are not created
• Timeline continues to show broken image placeholders
• Re-running Generate Thumbnails does not fix the issue

Relevant log errors

The add-on log repeatedly shows errors like:

Unable to run job handler (AssetGenerateThumbnails)

Error: /media/IMMICH/photos/.../IMG_xxxx.HEIC: bad seek to ...
heif: Decoder plugin generated an error: Unspecified (7.0)

[hydazz]

Is this on a raspberry pi (aka arm64)?

[sykim4468]

That's right. I'm running Home Assistant on a Raspberry Pi and using it with some add-ons installed.