I also play on Linux. But, I am playing the Windows build (not 'native Linux') via Proton. I do not remember why, but I think, I read something negative about the Linux version in these very Steam forums a while ago.

I did not play much of this game over the years, but do not remember having hat a 'corrupt save file' issue (which I would remember).

The save file is a straight-forward, uncompiled LUA file, right? Clear text. If you are invested in that save, can you 'check' it? Maybe compare it with a different save files? Maybe find what looks strange. Not sure what can be the issue.

I/O (read-write errors) are extremely rare and would point to a failing hard drive or corrupt memory (which this is likely not). A rare game bug is possible - cannot say from my end.

... and I assume you searched the forums and are sure, it is not as simple as THIS issue:

https://psteamcommunity.yuanyoumao.com/app/243970/discussions/0/412448792366918771/

Do you play with any mods? In any case, it could help if you share the your log and save in "~/.local/share/Klei/InvisibleInc/"

I think I got it working now. I'm guessing the problem was with the Linux version of the game. I told it to use Proton in the game properties, and now it actually loads the mission. Thanks!