Steam automatically updated KSP 1.11 to 1.12 this morning, and it soon became apparent that it broke the game completely (can't get into tracking station, can't get out of R&D, can't even quit the game except by forcing shutdown from Windows). But it doesn't seem to be on 1.12 any more, since about 1400 UTC it's showing as version 1.11 again, and now it seems to be working as before. Did they quietly roll it back on Steam, or is the version number an error? Or what? Everything seems to be working again now, but I hardly dare play in case they do something else to it and it wrecks my save.
This is why I hate automatic updates, they break things with no warning. Please give us the option to turn off automatic updates, there is no way to do that on Steam.
I have now copied the game to a different drive that Steam doesn't know about and will try playing it from there, in the hope that it will stop Steam/Squad messing with it.
