(FCP X) Error: DTD Validation Failed

There are two main culprits for this error message:

• The first culprit is having updated into either PluralEyes 4.1.12 or PluralEyes 2023.
  • Updates are obtained through the Maxon App
    
• The second culprit is having made any edits whatsoever in your FCP X project prior to sending it to PluralEyes.
  • Edits can include obvious things like cuts, effects, transitions-- or they can include more subtle edits like marking in/out points, adjusting sound levels when importing audio, or having made any FCP alterations whatsoever to the original raw footage/files.
  • PluralEyes does not support any edits having been made to the original timelines. You'll need to rebuild and/or re-import your footage with zero edits having been made.

If you can't, for whatever reason, update into the latest PluralEyes, there are three workarounds outlined below:

Workaround 1

1. Import media into FCP 10.6
2. When exporting XML choose "Previous Version (1.9)” from the FCP X export window 

Workaround 2

1. Import media into FCP 10.6
2. Export XML
3. Change the file extension of the exported file from .fcpxmld to .fcpxml 
4. Use the enclosed .fcpxml file (info.fcpxml) to import into PE4

Workaround 3 

Downgrade to the previous version of Final Cut Pro