So I installed A13 parallel to A12 and started it once to test it, didn't create world or game. When I now try to load my A12 savegame with the A12 version of the game, I just get a black screen. I would really like to finish my last colony so if anyone knows how to solve this I would be thankful.
Saves are pretty much never compatable with different alphas, if you want to finish the colony, load it with a12, not a13
move your a12 saves and config into a folder (in the a12 game directory maybe? up to you) then read the readme and set up the target on a shortcut to point at that, you may have ot clear the config from appdata ludeon folder. That might work.