Issue opening iMovie files on older Mac

Rich- thanks for the response. Here is what is odd about this. I was running El Capitan on my MBP and had saved iMovie libraries with that MBP to an external hard drive. I had not run it yet using the newer Mojave OS- so files were unconverted. I would have thought that if they ran on the MBP using El Capitan, that they would also run on the iMac using the same OS.

You mentioned version 10.1.12- I am only at 10.1.10-- hoping that would have made a difference?

Thanks again.

When I first upgraded it was 10.1.1. Just before I upgraded to Mojave it was 10.1.6

I have Carbon Copy clones of both states and I am thinking of trying them on the iMac- just to see if it makes a difference with iMovie. I might try copying iMovie from one of those backups. Any thoughts before I try?

Thanks, Rich.

Mark

Rich- I will post what happens. Thanks for the comments. I use the Macbook Pro for all the movie work I do. I just like having a backup in case the MBP has issues. I also like using the iMac, as it has a bunch of legacy files- including pictures that I sometimes want.

Also- I have multiple iMovie libraries saved on external drives- usually broken up by year or topic. I like having the ability to play or edit those. If, going forward, I am not compatible then that is the price I pay for keeping current :)

Update: I was able to load iMovie 10.1.6 to my iMac. Able to open most of the older files but I may have "peeked" at one of them with my MBP- so it was upgraded and can not be opened (at least that is my guess). It is a shame that Apple does not have a way to save a library in a "prior version" format. I will just have to keep those library files separate if I want to be able to use the iMac.

My next experiment will be to see what happens if I try loading 10.1.12 onto the iMac. I expect issues, but it is worth a try. That would solve my problem.

Thanks for all your responses, Rich. As predicted, the latest version of iMovie came up grayed out and would not open on the iMac- error message stating it was too old. Anyway- I plan to play around with the new iMovie on my MBP and see if it is worth keeping or if I should shift back to the older version for compatibility reasons. Worst case, I assume I can open up the library package and import the clips if I absolutely need to go back (that is my next experiment). Will definitely be keeping the iMac- love the large screen and still have a bunch of legacy material on it.

Mark