Final Cut Pro Missing files, relinking doesn't work, FCP knows where they are, still displays the error (not a missing effect)

SSDs work best when formatted with APFS (GUID Partition Map). HDDs work best when formatted with Mac OS Extended Journaled (GUID Partition Map). You don't want to use FAT32 or ExFAT formatting (FYI). It's always good to check this when using a new drive or sharing a drive with someone else.

I'd be wary of disconnecting any drive that is used/referenced by a Library while FCP is running (and the media is used by an open Library). I've done things similar to what you've described (i.e., creating a proxy-only setup for a laptop) without any issues.

You might consider creating a new test Library and importing just a small number of files/clips to build a test multicam clip and test Project/timeline. Switch between proxies and original/optimized media (don't disconnect any drives). Then, try closing the test Library and quitting FCP. Now, unmount the drive with the original media and relaunch FCP and open the test Library. Edit with the proxies (make a cut or two). You may see missing media icons/warnings if you choose anything but prefer proxies or proxies only in the Viewer's View menu.

Close the Library and quit FCP. Re-mount the drive with the original media. Start up FCP again and open the test Library. If you switch to use original/optimized media, things should automatically relink. Or, manual relinking should work.

Let us know how this works out.

It's good to try with a small test case first, in order to see if it fixes the situation. If it fixes things, then it would be a good idea to scale it up to the entire project for more testing (as you mentioned). If not, then we can consider other options...

A couple of thoughts...

You might try making another new test Library, importing some media, making proxies, etc. (as you did already). With the Library open and FCP running, unmount the HDD in the Finder, continue to edit with proxies. Then, you could try re-mounting the HDD and switch back to original/optimized media in FCP. The idea is to "unmount/disconnect and remount/reconnect" the HDD with FCP running and the Library open.

(What I suggested you do and what you seemed to have done should have worked fine, and it did. The idea being that unmounting/disconnecting the HDD while FCP is running and the Library is open, might cause an issue. So, by only disconnecting the HDD when the Library was closed or FCP not running may have helped.)

The other comment is that FCP considers some media formats as "pre-optimized" or not needing optimization, so it won't do anything with that media. ProRes media is one of those formats. I believe WAVE/AIFF files are another. Also, some files, such as MP3 audio will be automatically "optimized" regardless of any setting in FCP (and made into a QT .mov audio file, in the case of some/most/all MP3 files). The "auto-optimization" can happen with some other files, but I'm not sure exactly which ones.

I would imagine (unless someone else chimes in with a better idea) that as long as you don't unmount/disconnect the HDD while FCP is running, you should be okay. I don't know if the fact that you changed the SSD to APFS before running your tests mattered, or not. Lots of moving parts. I agree it's nice to know what might have caused the original issue, but knowing how to do things "properly" may be all the solace you'll get...

The OS shouldn’t allow you to unmount the drive if the files are in use by an application. Switching to proxy shouldn’t be enough to release the original media I wouldn’t have thought. It shouldn’t if it does.

Tom, I can verify that I was able to unmount a drive with the original media on it. With the View menu set for original/optimized, I got a macOS warning saying it wouldn't dismount the drive. After switching to proxy only, I was able to unmount the drive. And, after remounting the drive with the original media, everything automatically relinked...

You'd think in over twenty years of editing I would have tried unmounting a drive while FCP was running (back to version 1.5 or 2). But, this test was the first time. Go figure... ;-)

It does make me wonder about whether FCP allows a drive to be unmounted when it shouldn't. In my simple test case, the original file was on a separate drive from the Library or temporary (proxies, caches, etc.) file locations.

As already stated, if both drives are HFS+ or APFS (or a combination), you should be able to dismount the media drive, unplug it, reverse that sequence and the library on SSD should automatically relink. If that doesn't work manual relink should work.

If somehow the 8TB drive volume name got changed, then auto relink will not work. The inode and pathname to each media file includes the volume name, and changing the volume name (accidentally or any other way) will prevent the relink.

However manual relink (in bulk) should work -- IF every media file has a unique filename. If there are duplicate filenames among the folder tree, I don't think manual bulk relink will be reliable. In that case, the only thing FCP knows is the filename and the file parameters. If there is a descriptive pathname that differentiates two duplicate filenames file like /Saturday Concert/First Act, it has no idea about that. If it finds another file with the same name, it will fail a metadata compatibility check. This is a good example of why it's important to have globally unique media filenames.

In a case like this, the symbolic links (symlinks) in the library still have the pathname information for where FCP *thinks* the files are (or were). Unfortunately that cannot be displayed for multiple files using Finder or the FCP UI (I don't think. I vaguely recollect Tom mentioning some method but I can't remember it).

Using terminal you can go into the library to the EventName/Original Media folder and use these commands. In this example, the library name is FX6Export2 and is located in the user's /Movies folder, and the Event name is A7S3Test.

cd ~/Movies/FX6Export2.fcpbundle/A7S3Test/Original\ Media

ls -l

To list the symlinks and their target location. You can also do 'ls -l > symlink.txt', where symlink.txt is a filename you provide. You can examine that with Finder, TextEdit, etc, and search for filenames. Example of output in the above case, where the original media file name is JDM0899.mp4, when imported with "leave files in place" FCP creates a symlink which is a small placeholder file that points to the final location of that file.

lrwxr-xr-x  1 josephmarler  staff  64 May 16 11:00 JDM0899.mp4 -> /Volumes/16TB_SSD/A7S3_TestClips/PRIVATE/M4ROOT/CLIP/JDM0899.MP4

lrwxr-xr-x  1 josephmarler  staff  64 May 16 11:00 JDM0900.mp4 -> /Volumes/16TB_SSD/A7S3_TestClips/PRIVATE/M4ROOT/CLIP/JDM0900.MP4

lrwxr-xr-x  1 josephmarler  staff  64 May 16 11:00 JDM0901.mp4 -> /Volumes/16TB_SSD/A7S3_TestClips/PRIVATE/M4ROOT/CLIP/JDM0901.MP4

If the link is good you can examine it in Finder, but (ironically) if there's a problem and you *really* want to see where the symlink points, Finder will not show that. You must use terminal or some other tool. There are some 3rd-party MacOS file managers that allow display and manipulation of symlinks. As a side note, Finder calls symlinks "aliases" but that is incorrect terminology -- it is a symlink.

The FCP relink dialog will show you the symlink target in grey letters at the bottom of the pane -- IF relinking a single file. It will not show you hundreds of symlink targets.

In FCP if you can right-click on the clip in the Event Browser, pick "Reveal in Finder", it should Open a Finder window, and highlight that corresponding disk file. If it does that it's using the symlink to get there. That means it's working, at least at that moment.

I don't understand why FCP would persistently show "Missing File", yet right-click on that red thumbnail and selecting "Reveal in Finder" would work.

Are both of your external drives either APFS or HFS+ (ie, MacOS Extended Journaled)? In Finder if you select each drive and do CMD+I to Get Info, what format is the 2TB and 8TB drives?

Do either of those drives go through a USB hub or junction box of any type? Do either of them use a non-OEM USB cable? There are often problems from doing either of those. However if a file briefly drops off line and a clip goes red, upon restoration of the connection, FCP will normally see the clip and the thumbnail will go from red to a thumbnail image. You generally don't have to relink or do anything fancy, at least on APFS and HFS+ drives.

You can run Disk Utility First Aid on both drives to make sure the filesystems are OK.

Richard, thanks for the update. I was just composing a post asking you to check why optimized files were there. You beat me to it!!

The first thing I do on a new FCP install is turn off "Create optimized media for multicam clips". It is so ingrained that I didn't even think to ask about that.

It's possible that config is on by default for legacy hardware. Newer machines don't need it. Also since 10.4.9, FCP has had the option of View>Proxy Preferred, which avoids two problems: (1) Proxies being required on all clips, whether needed or not, to avoid some showing as red in proxy mode, and (2) 50% proxies on a mix of 4k, 1080p media will produce visibly lower-resolution playback on the 1080p clips.

For the above reasons it was sometimes necessary to use optimized media before 10.4.9, but that is no longer required.