I have not seen this before. I encode a 720p file using the H.264 480p widescreen codec and get an mp4 with no data and an xmp sidecar file. I have tried using the Vimeo 480p widescreen variant with no success. I encoded two file earlier yesterday with no issues, then this popped up.
I am on MacOS 10.13.5 High Sierra, and using the latest version of Encoder. I uninstalled and re-installed Encoder. No luck. I also tried with the 720p codec, but had issues. Another point of note; it took only around 20 minutes to compress a 55 minute piece of video.
I went to my laptop, running an earlier version of encoder and MacOS. I was successful on the laptop, but the time was extreme.
So, my question is what changed? Are MacOS High Sierra and the most recent version of Encoder incompatible?