iMovie "Missing File" issue. "Consolidate Library media" not working

The likely cause of the problem is that your external drive is formatted ExFat. ExFat and Apple are compatible for just about everything except an iMovie library. An iMovie library must be stored on a drive formatted Mac OS Extended (Journaled) -- best for spinning drives -- or APFS -- best for flash drives, but both work. If you store it on a drive formatted other than those formats, you can lose data and have other communication problems. That might explain the "Missing File" issue.

If you reformat your drives, be aware that reformatting erases all data on the drive. So you must first back up any data before reformatting.

I haven't fully tested this, but I believe that If you import a file with the same file name as one that is already in the library, it will just replace the file that is already there. So it wouldn't add to the library size. I tried this with one clip and I could not locate any duplicate in the Show Package Contents, Original Media folder, for the project. It just showed one file with the original file name. However, when I changed the name of the clip and then imported it, a duplicate file was created, so that would increase the library size.

You might create a test library and experiment a little.

-- Rich

What is the format of your external drive? What procedure did you use to "separate out" your iMovie libraries?

Did you do the "consolidate library media" procedure on the main library before splitting it out? When you refer to "clips" and "files", are you talking about the projects that are still in editable form? When you see a "Missing File" designation are you talking about missing clips that are within a project, or the project icon itself?

It seems to me that the procedure would be to consolidate the media in your 476 GB library, and then create a new library, and then copy (not move) the projects you want, over to the new library. Not sure that it is necessary, but probably would be good to do a "Consolidate Project Media" (from the projects browser screen) on each project before you copy it over to the new library. That should insure that you don't get "Missing File" designations. If you are still getting them, it may mean that the original source media is not on your Mac, or the storage location is on a drive that is not plugged in, or the external drives are not in a correct format. They should be Mac OS Extended (journaled) or APFS. I suggest trying it with a couple of projects to see if it works.

Some screen shots of what you are seeing would help.

-- Rich

All photos and videos imported into iMovie are stored in Original Media folders specific to each project or event into which the media was imported. The Original Media folder is a Finder folder located in the iMovie library. It contains a full-sized duplicate of the original clip imported into it. The original clip itself will remain in its original location. The iMovie project itself contains no original media, but rather tiny sized thumbnails that refer to the original clip in the Original Media folder for that project. You can view the Original Media folder by selecting any clip in the project and doing a File/Reveal in Finder. That will cause the Original Media folder to pop up with the name of the selected clip highlighted. Also displayed will be the file names of the other clips in the project. There you can copy (not move) the media anywhere else that you want. You can also delete the media from the Original Media folder and that will remove it entirely from the iMovie system. However, deleting or moving a clip will disable it (i.e, "missing file") from all projects that might be referring to that clip.

Another way to view the Original Media folder for a project or event is to control-click on the Library's icon in the Movies folder or wherever else you have the library stored. When you control-click on the icon a pop-up menu will appear containing an option to Show Package Contents. Click on Show Package Contents and you will see a list of folders for each project and event in the library. Click on one of the projects names and its folder will open to show several subfolders, one of which is titled Original Media. Open the Original Media folder and you will see all of the media that is contained in the project or event. While you cannot play the project itself in the Show Package Contents folder, you can play the media that is stored in the Original Media folder for the project. You can play the media there or copy the media and store the copy on your desk top or anywhere else that you want. You don't want to actually move out the media, or make any changes whatsoever, or you risk corrupting your iMovie library and/or the project as discussed above.

The projects themselves can not live outside of an iMovie library. You would need to move or copy the project to another library as you have been doing.

However, never move, alter, delete, or in any way change anything in the Show Package Contents.

-- Rich