To get it out of the way, I can't get a log because the game doesn't even start, no log is ever generated with either the Debug or the Normal builds.
I finished BP today and wanted to play something else, so I picked BtA, when I got the following error:
My "Preferred Engine Stability" setting was on Stable, so I tried RCs. After the RCs downloaded, I tried running BtA, but nothing happened besides the "FSO is launching..." prompt briefly flashing on Knossos' status bar but the game never actually started.
I tried reverting back to Stable and it failed again. Then I tried running a mod I had been playing: BP. The same "FSO is launching..." message, but no game.
I then tried running just Retail FS2 and same result "launching..." then nothing. Then I tested running Retail FSO with 3.8.0-3 instead of 19.0.0. This worked, and all mods that are compatible with 3.8.0-3 still work too.
So I tried Verifying File Integrity on FSO and it said there were no problems.
I outright deleted my 19.0.0 folder to force it to redownload. However, the problem persists after the redownload.
(I also tried rebooting my computer a few times along the process described above)
I have no idea what to try anymore.