Recover iMovie data from corrupt library

Hello,

I had the issue where iMovie hanging while validating a library.This thread gave some hints : Stuck on "Validating Library" - Apple Community

The open files list of the hanging process in the Activity Monitor showed on which item the validation was stuck. So that was a "suspect".

After creating a new iMovie library and copying all projects, except for the "suspect item" to it, the new library passed validation (hurray!). I followed the steps that were described in the previously mentioned thread. (Thanks!).

But how can I recuperate the media in the "suspect item" ?

Copying only this item to a new library did not help: the media were not visible in the new library.

Is there another way to get these data back in usable state?

The original failing library and all its contents (valid items and the invalid item) is still available.

Thanks for any useful advice,

Frank