What you are doing is called transcoding and I can't guess why this file is problematic but Windows Explorer has done such since say 1995 with my story about a trip to Redmond to ask about that. Microsoft's answer was telling and in short they don't consider it a bug!
I seem to be running into a bug with VLC Media Player. I wanted to convert/save an mp4 file to an mp3 file. Nothing major, I do it all the time. However, after several tries and even updating my VLC Media Player, the apparent bug persists.
This is what happens: when I click the final button to start the file conversion, there is a pause of nothing happening (normal), followed by the top bar of the VLC interface boundary wigging out with "not responding" and maybe something else (less normal). I had my Task Manager open and checked to see what it had to say about it, and it informed me that the CPU load being used by Windows Explorer was claiming up into 30, 40 even 50 percent--so much so, that VLC cannot even run. Has ayone out there run into this same problem? Has anyone out there ran into a solution?
Specs, if they help: Windows 8.1 64 bit on a Dell Inspiron 15.