What did I do?
Attempted to apply an update to a windows copy of Factorio 0.18.31 by running the following:C:\Program Files\Factorio\bin\x64\factorio.exe --apply-update core-win64-0.18.31-0.18.32-update.zip
At the same time, I also have a mod enabled, that I'm developing, that doesn't load (yet).