iMovie projects missing files after external transfer

With storage space becoming more scarce with the quality of video and file sizes these days, I've always had to move my iMovie libraries on to portable SSD drives. I usually use Samsung SSD's that have a transfer speed of 1gb/s and never used to have any issues when transferring the entire iMovie library over to a portable drive.

In more recent times, rather than moving the entire library across to the portable ssd, I've preferred to copy an iMovie library to the portable drive and then transfer projects to that library on the drive once I'm finished with them on my Mac. I did try editing directly off the portable drive thinking that the speeds would be sufficiant, but it doesn't take long for iMovie to start lagging when editing directly on the portable drive.

The issue I have is, when I move the project to the library stored on the portable ssd, if it is a small project that has maybe 10-20 video clips, the project usually transfers fine. I often create videos that have well over 100 video clips and once the project is copied to the drive "successfully" I will open the project on the portable drive and there will me missing files.

The weird part that doesn't make sense to me is it's totally random what clips will be missing and doesn't seem to be any pattern to what files go missing. Sometimes it's only a few clips, sometimes it's a few more and sometimes it looks like it barely tried. Sometimes... it works as it should. During the transfer process I watch the loading circle in the top right of the screen that shows how many files have transferred out of how many total files that need to be transferred. I will watch until it is complete and the project will disappear from the library stored on my Mac. I'll then open the library on the portable drive to find the missing files.

Also, just to note: when I say the file is missing, the video in the media section will go blank and when you hover over it, it will say missing file and usually show the name of the missing file. The clip that I have taken from the video will remain in the video timeline, but again, will show a blank screen in that section of the video saying that the file is missing.

Here's where it gets weirder. If it shows missing files, I will then transfer the project back to my Mac's iMovie library. When I re-open the project once it's been copied back to the Mac, the missing files will no longer be missing. I will then transfer it back to the portable drive for a second time... and sometimes it will work and the files will no longer be missing. Sometimes, some of the missing files will return, but not all of them and I will go back and forth from drive to drive until they all show up on the portable drive. Sometimes if I do it too many times, or if the app crashes and iMovie restarts, the missing files on the portable drive will no longer show the name of the missing files and at that point, I know that the missing file is lost forever. Something else I've noticed is, sometimes when everything looks like it worked as it should have and the project on the portable drive shows all the files as being copied over successfully, the next time I open that project on the portable drive, some of the files will be showing as missing... and again, they cannot be recovered when this occurs.

I film with 4 different cameras that range between my iPhone, a DJI action cam, a Panasonic Handycam and a Sony mirrorless camera. It doesn't matter what device the video file comes from, it can still go missing. Some of my videos will be a mixture of all of these different cameras and files will still be missing. There is no pattern that I can see that determines how the file shows up in the project as missing. The only thing that I have kind of noticed is that it seems to work better if I transfer a project that has a smaller number of videos first, before transferring a project with a massive amount of clips. If I transfer a project with a huge number of videos straight off the bat, the more files seem to be missing.

I have tried consolidating the files as online help as suggested, but everytime I've tried to consolidate the files before transferring, iMovie tells me that there are no videos that need to be consolidated.

I have other editing programs that I will use for certain things and I am most likely going to move over to them. The reason I like using iMovie is because of it's simplicity and the fact that I work very quick when editing with iMovie. I understand the other editing programs will be better and give me more options, but if iMovie did not have all these little glitches, it really is a good editing tool for simple video edits.

Hope this all made sense and if anyone can resolve this issue or figure our why it's happening I would love to know.

Thank you for reading.