I'm experiencing the same thing. Certain mp4's and mov files are coming back with the same "media offline" message. When i try to reconnect the media, I get an error message that says that the two files don't match up and therefore the file will be deleted from the project and from any sequence that it's in. When I press OK or go back in the bin and delete it manually, I usually try to re-import it. When I try to bring the video file back into Premiere, it comes in as an audio file as if the video doesn't exist. Also with certain of my Apple ProRes files, the audio glitches.
Hi PaulFarris, TristyDee,
Sorry for the trouble. It could be an issue with the old media cache. Please clear the cache & check.
Here are the steps: FAQ: How to clean (delete or trash) media cache files?
Let us know the status.
This will fix your problem.
This easily converts .mov files to a codec that can be imported in to the current Premier Pro. I just tried it and it works. It's for Camtasia but works the same for Premier Pro https://www.learncamtasia.com/cool-resources/convert-alpha-movs-to-work-in-camtasia-9/
Just follow the 5 min video and download the files below it.
I can now import all my older .mov alpha channel videos and they work as they should do.
Same problem here -- but it is insane that I need another video editor (which I have) Camtasia to convert a file to use in Premiere which i'm paying lots of money for to be my primary video editor.