Compound clips permanently corrupted (dark gray, unopenable) across library AND all automatic backups. FCP 12.3

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Level 1

4 points

Compound clips permanently corrupted (dark gray, unopenable) across library AND all automatic backups. FCP 12.3

Final Cut Pro 12.3, macOS Tahoe. All compound clips in my library turned dark gray and unopenable overnight, between two normal work sessions, with no crash, no macOS update, and no software installation at that time.

This is not a media problem: logs show all source media files load correctly. It's not a plug-in issue either: XML export shows the compound's internal resource data is missing entirely ("Resource not found" on media UIDs), so the corruption is in FCP's own compound clip data model.

Worse: the corruption is present in every recent automatic backup too, not just the live library. Only a project duplicated earlier via "Duplicate Project as Snapshot" (which embeds independent copies of compounds) retained healthy versions, confirming this is a genuine data-loss bug, not user error.

Posting this so others hitting the same issue can find it and confirm they're not alone. Already reported to Apple via the Final Cut Pro feedback form. Not planning to follow up on this thread, but if you've found a fix, please post it for others.

Posted on Aug 6, 2026 1:21 AM

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Answer 1

terryb

Level 4

3,654 points

Aug 7, 2026 10:50 AM in response to vanderbo

I recall losing a few compounds in a library has happened to us a couple times over the last 8 years. I think both instances had a motionVFX plugin with a drop zone involved in the compound. There were only a handful that broke, so the quickest solution was to rebuild them. Since you have a backup from a snapshotted project, you should be able to copy between libraries and replace the broken compounds.

On the chance that there's a system level issue that's causing this (Cleaners, ancient software migrated to current OS, etc.), paste a report from https://etrecheck.com using the "Additional text" button below in your reply.

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Answer 2

vanderbo Author

Level 1

4 points

Aug 8, 2026 5:30 AM in response to terryb

Thank you. Unfortunately, in my case, all the compounds were lost, regardless of their effects, and it wasn't possible to recover them from a snapshot or a backup of the library. I've reported the issue to Apple. This took up an entire day trying to resolve it, fruitlessly. Spending more time on it would be unreasonable.

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Answer 3

terryb

Level 4

3,654 points

Aug 6, 2026 9:13 AM in response to vanderbo

Where is the library stored? What is the disk format where the library is stored? Is the media stored inside the library? If stored outside on another disk, what is the disk format?

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Answer 4

vanderbo Author

Level 1

4 points

Aug 7, 2026 5:19 AM in response to terryb

Hi, library and media are on an external SSD, APFS formatted. Most media files remains external.

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