Unknown Length after exiftool processing

[jcallaway]

I batch processed a few hundred MP4 files with ExifTool (conditionally populating the Copyright tag) and a subset of those files are now behaving unusually, only in MediaMonkey:

• I batch processed 310 video files. All files play without issue in VLC, MediaMonkey, and Plex, and the tags are as expected in MP3Tag.

• In MediaMonkey 81 of the files are as expected; the remainder display "Unknown" in the length field and don't display any tags.

• I don't see anything in the ExifTool processing log to indicate a difference between the 81 and other files.

• I've tried rescanning, restarting, and optimizing the database in MediaMonkey: no effect.

• If I populate a new tag in MediaMonkey it does not appear in MP3Tag and vice versa.

Any idea what that might indicate? This is my 1st test folder of hundreds, so before batch processing thousands of files I want to be confident that I'm not breaking something.

[Lowlander]

Please share an MP4 file with this issue with Support. I don't recommend proceeding further as a corruption may be introduced by ExifTool.

[jcallaway]

Thanks very much for the fast response. I've created a support ticket with an example file and will hold off on any further processing for now.