During the last week I've had the same game-breaking bug pop up, and I think I've figured out what causes it.

    So here's what happens: seemingly out of nowhere a big, black vertical line pops up in the middle of the screen for just a short moment, and when I move the mouse out of the way, the *entire* UI for the game fades away. If I don't move the mouse for a few seconds, it comes right back, but continues to fade away as soon as I move the mouse around once more. Very frustrating bug, can't click anything, and it sticks to the save files, effectively rendering those games unplayable.

    I do believe I've figured out what causes it, though. The big black line that popped up just as the bug procs? It's the menu backgound for "potential ransack from trade routes", which I got from mousing over my capital, during a game where I'm playing with only one city, while allying and trading literally everything with 9 other empires. My guess is that with that many trade routes converging on one single city, if you by accident open up the "potential ransack from trade routes" menu, the game simply cannot deal with that many trade routes, and so the bug occurs. If I manage to navigate my way blindly back to the main menu of the game, the bug persists there aswell, with the invisible UI now affecting the entire main menu. Restarting the game removes it though, until I open up the corrupted save file again. 

    Exactly *why* it turns the UI invisible is unfathomable to me, but whatever the case may be, I hope this helps someone trying to fix this bug. Good luck, and thanks for making the game! 

I've been trying to figure out how to convert save file to .zip, but I'm far from capable when it comes to computers, and I don't know whether the converting websites are legit or not. A helpful suggestion for a legitimate and easy-to-use website would be appreciated!