Final Cut Pro exporting issue

Try deleting the settings (aka preferences).

Hold down the command and option keys as you launch FCP until a window appears asking if you want to delete the settings.

Click the Delete button and FCP should open with an empty project/library.

You can then navigate to the library you were working on and double-click it.

Delete preferences, as Ian recommended, and try opening the library, and do so any time there is a crash, as the crashes tend to corrupt the preferences.

If it still crashes when opening the library, it probably means that the library itself got corrupted, in which case you may try opening one of the recent backups. Backups of your library are stored, by default, saved to "Final Cut Backups", inside your Movies folder. The backups keep only the library structure, and not the media, so if you go with a backup you will then need to relink the media.

Hi(bonjour),

Did you try to reset preferences and start a new empty project from scratch, without your external disk plugged? If it’s work, I would first explore the integrity of your external drive with Disk utility, under SOS item to get a diagnosis.

If you can open the drive, are you able to copy some clips from external to your newly created library on your internal drive?

Michel

There is a fundamental difference to having media on an ExFAT or NAS drive vs having the FCP library on those. Except for exports, media files are read only. FCP does not ever write to a media file. By contrast the library is a complex set of SQLite databases. FCP is *constantly* writing to those.

Those writes are grouped in transactions, similar to when you transfer money from a checking account to a savings account. They absolutely must be fully applied as a group, or fully rolled back. The SQLite datbase uses a concept called "write ahead logging" to try and achieve that. However it is limited by the cooperation of the underlying filesystem. The enqueued writes must take place in the requested order and the buffers must be flushed when the app demands it. If this doesn't happen the database can be damaged.

Another case is if the system crashes, hangs or the disk is suddenly disconnected. The HFS+ and APFS filesystems have transactional characteristics that to help ensure the disk metadata stays consistent in such cases. ExFAT and NAS servers do not have those attributes -- either at all or with the same reliability of a local HFS+ or APFS drive.

Although it was not revealed until late in the thread, this customer had their FCP library on an external ExFAT drive and it disconnected. If that happened when transactions were underway within the SQLite databases it could easily damage data.

There are methods whereby an NLE can safely place a SQL database on a remote server, but it involves a purpose-built design that issues SQL calls in a client/server architecture, not by doing low-level "dumb" I/O calls. E.g, Resolve can be configured to us a PostgreSQL client/server database, in which case it's safe. But FCP uses SQLite, which is an in-process, not a client/server database.

SQLite on macOS uses certain proprietary calls such as fcntl(fd, F_FULLFSYNC) to ensure I/O cache buffers are flushed when requested and in the right order. If the SQLite database is not on an HFS+ or APFS locally-attached drive, that can be unreliable. It can be ignored, translated incorrectly, or acknowledged prematurely by the lower layers, and especially by the intermediate layers on a NAS.

My documentary team sometimes uses a QNAP NAS for media and in a few cases we've used FCP libraries on the NAS. However, we are fully aware of the risk, and we always have multiple backups, including a series of library XML exports. But we mainly try to avoid using an active FCP library on a NAS.

When it asks you if you want to reopen, DON'T. You are apparently trying to reopen the corrupted library, and that will probably just crash again and again.

You may have to go back in the list of backups until you find one that works.

And ALWAYS, after any crash, delete the preferences once again.

Trash the preferences, create a new Library and project and stick a couple of random clips in it.

See if it exports . . . if it does you know the fault lies in the original library.

Do not store libraries on an ExFAT drive. You might get away with it for a period of time but eventually there will be corruption. Apple's recommendation is now APFS on both SSDs and spinning disks.

Format storage devices for Final Cut Pro, Motion, and Compressor - Apple Support

Try double-clicking the Library.

I'm glad for the progress. Was your damaged library on the Mac internal drive or was it on the external drive that disconnected? Is that drive formatted ExFAT, HFS+, APFS, or what? Your phrase "when I navigate to the project on the ext drive..." implies that your library might have been on that external drive. Is that possible?

Each time you tried to open an FCP library backup in /Movies/Final Cut Backups.localized, you said it still crashed. Did that really happen, or did you open the backup OK, then you tried to open a crashed library on your external drive?

FCP produces a series of library auto-backups. The number and frequency varies based on several things, but normally there are several backups available. Most of those are not even opened as files, only the most recent one is. It should be extremely rare for an older library back up to be damaged.

We are happy your current situation seems somewhat resolved, but if you could provide these details that could help people in the future.

ExFat with macOS, especially FCP, spells trouble.

That may or may not be true.

Apple's wording is . . .

Some storage devices are sold pre-formatted with Windows file system formats such as ExFAT or FAT32. They might not perform as expected with Final Cut Pro, Motion, or Compressor.

To me the wording suggests they are guessing that problems might occur having not tested FCP on exFAT and suggesting you play safe by sticking to APFS . . . a bit like Panasonic etc. saying they cannot guarantee that third party batteries will work correctly.

Over the past decade I have had several instances of corrupt frames or clips bricking projects whilst using correctly formatted drives.

I would like to clarify my last comments.

I was not suggesting that people should use exFAT drives blindly.

As FCP has been tested on APFS, that is the formatting that should be used ideally BUT there are occasions when you need to use a drive suited to both Mac and Windows. In my case I cannot use an APFS drive with my TVs. So I use FAT32s to play my movies. I use separate APFS drives to edit my movies but understand that some people may not wish to purchase extra SSDs.

However, if it is important your drive covers both systems I don't think you should worry about using it with FCP . . . it's just that it's not been tested and theoretically may be more prone to glitches.