I've recently been encountering strange issues when Importing .MOV files into Premiere 2019 or 2020, where I'd get a "File Import Failure: We were unable to open the file on disk" error. The error also occurs in After Effects, with the same files.

The files import or open without issues in every other video application I tried (DaVinci Resolve, Quicktime Player, Screen (Videovillage.co), VLC, IINA, Telestream Switch Pro & FCP-X).

After a bit of sleuthing, I figured out that the problem only occurs with .MOV files that were specifically transcoded out of Apple Compressor 4.4.8 (which is the latest version for macOS Mojave, as of 2020-10-17), AND also contains audio tracks.

MOV files that were encoded as "Video Only" out of Compressor 4.4.8 did not exhibit the import issue. Nor did the same file transcoded out of Compressor 4.3.2 (last High Sierra compatible version) with audio tracks enabled.

.MOV files transcoded out of other apps (such as EditReady) did not have any issues importing.

Changing the video/audio codecs or encoding parameters used to transcode them did not have any effect on resolving the issue.

Files that were transcoded to non-MOV containers out of Compressor 4.4.8 (e.g. .MXF & .M4V) all import fine, regardless of the presence of audio tracks in the transcode.

Deleting the physical audio tracks from the suspect .MOV files (using Digital Rebellion's "QT Edit" tool) did enable them to be imported without error. But obviously, this isn't a particularly ideal workaround if your camera footage has sync'ed audio in it.

So there seems to be some sort of bug that is causing File Import failures with .MOV files that were specifically encoded with Compressor 4.4.8 .mov files, AND also contains audio tracks in them.

I was first inclined to submit this issue to Apple as a bug, but the fact that no other application on my Mac (macOS 10.14.6, with latest Apple "Pro Video Codecs" package installed) seems to have problems importing the same files makes me think it's an Adobe specific bug.

Here are my test files, if anyone wants to help investigate:

Master ProRes .mov file (this is the source master file I used for my testing): https://d.pr/v/k6DYrJ

Test Transcodes: https://d.pr/f/MGIgWv

The Test transcodes in the .zip file contain the transcodes of the Master ProRes file, in various formats, from Compressor 4.3.2, Compressor 4.4.8 and EditReady 2.6.5. All the Compressor 4.3.2 & EditReady encodes import into Premiere/AE without issue. The only encodes in the Compressor 4.4.8 folder that import fine are the .MXF and .M4V files, as well as the .MOV file which was encoded with the "Format" option set to "Video" instead of "Video and Audio"

My current workaround is to "rewrap" (NOT re-transcode) the offending files to new .MOV files, using EditReady. This appears to strip out whatever internal inconsistencies existed in the original transcode, and allows them to be imported into Premiere again.

Here's a link to an EditReady-rewrapped version of the "compressor4.4.8-Apple ProRes 422 LT.mov" file. This imports into Premiere without issues, and is not re-transcoded, either.

https://d.pr/v/I0DiZg