A colleague just advised that since upgrading Mac OS X to Yosemite he can longer open/access any of his digitally recorded movies that were filed in iMovie. All attempts at getting other applications to do the job failed.
Yosemite apparently does not include iMovie among its applications (unless one heads to the Apple Store and pays for it).
Any thoughts on the matter? Such as tacking on some extension which could get an included app (eg, iTunes) to open the movies. Other possible workarounds?

You don't say from which version of OS X he upgraded, but is his current iMovie the latest version?

I suspect that the problem lies in his user account, since iMovie is not incompatible with Yosemite; I just opened my version.

How about logging into another user account (or create one) and see if they can be retrieved from iMovie in this test account.

Don't know; probably from Mavericks.
Whatever it was, iMovie disappeared from his library of apps upon upgrading to Yosemite, and he apparently has no way of recovering it (AFAIK). So he's probably just going to bite the bullet and pay for a new download.

In a similar situation I've given Apple a call and they applied a purchase to my Apple ID and I went to the store and was able to just tap the (cloud/down arrow) icon and download it.

Unless Apple can do it online, that isn't an option. He's 800 km / 500 miles from the closest Apple Store.

The APP Store, that is.