Hi jedao, thanks for getting back to me
Appreciated and I can understand the annoyance, for sure, and on thinking about it later I imagine you maybe meant the post had disappeared from the Steam forums (?), but I had simply moved it from the General category to the Technical Support category when I replied, to keep things organized (so it would still appear in your notifications as normal when I replied, but not if you're just browsing the General category without switching over to the other board).
As to the issue, so you don't have a crash.log, eh? Makes sense I guess since from what you've posted there (I'm assuming it's the end of the run.log) it looks like the error is that it's trying to load a saved game, one which is seemingly corrupted (this seems possible in very rare cases due to external factors like Steam, or other system oddities, which is why I added an automated backup system to be able to recover saves and progress even when this happens).
That's what the line "Unserializing saved BattleScape" means there, so given that you have indeed attempted to reinstall this elsewhere etc, yep Steam cloud keeps restoring your old broken file xD
If it happens again in the future when you're playing, let me know and I can tell you how to recover even broken saves, although really this shouldn't be that common an occurrence...
But anyway first let's deal with this particular issue, which requires that you 1) delete your saved game (the "user/save_v57.sav" file) then 2) make sure that Steam does not restore it via the cloud, which is active by default:
In Steam go to Cogmind > Properties, and under the General tab there's a section Steam Cloud in the middle there, make sure to unclick the "Keep games saves in the Steam Cloud for Cogmind."
After doing this it should start up normally. Try that and let me know how it goes
(Not to overload you with info, but technically if you have other .sav-extension files in the user directory, you can rename the last-dated one to "save_v57.sav" and it will likely be able to continue the run you were playing before this occurred.)