Re: Weird issues with Episode 6 and mp4

OK. There's nothing wrong with the system. There is something wrong in the user account though.
Generally this would head down two possible paths. Something corrupted or otherwise damages or something conflicting.

Of course one solution would be to dump the user account.

If you're adventuress and there's a lot of work invested in that user account there's some things you can try in your own order of preference.

Delete all login items and make sure there are no background tasks or programs running (even time machine, just in case). Basically anything that might kick in that might impact using a file or writing a file to the drive.

Basically if something is interrupting the write function in Episode it can be either the final file write or it could be Episode's creation and access of the temp buffer being written to the drive.

Since you say WMV, test using settings comparable to what you used for .mp4 except do it in a .mov container. Then try the same thing but using a different targeting codec so as going to ProRes .mov again. This might determine whether it's codec or container specific in the user.

Another place to look may be third party Quicktime plugins which, while system wide, might be running into an issue/conflict in this user. If you were to remove all the third party Quicktime plugins and the encode works, it would indicate this is the issue. That WMV worked an MP4 didn't might hint at this.