Have you ever been working on a lot for a long while and when you go to switch from Build to Buy mode (or opposite) your UI glitches out on you? Like, more than half of it is missing on the right and there is no response when you try clicking on build, buy, undo, everything?
If this happens, just simultaneously hold down the ‘Shift’ key and the ‘F4’ key. The game will take you to some random lot, and from there you can go into Edit Town and save the lot you were working on to the Library. Then you should do a ‘Save As’ and close your game. After closing, delete your compositorCache.package file. Now you can safely resume working on your lot.