Unable to find installed version of The Sims 3 base game

[HazelEyes]

I have a new computer and just this weekend I installed the base game, Ambitions, all the patches (using the MTS patch updater, not the launcher) and CAW. I have been using CAW just fine, but when I tried editing in game, I got this message.

"Unable to find installed version of The Sims 3 base game"

Googling provides no answer, neither does a search of either MATY or MTS, unless I've been using the wrong search terms.

I suspect this might have something to do with not having EADM. I thought about the launcher, but I have it, I just don't run it. Any ideas about how to fix this would be most welcome.

[wizard_merlin]

Did you try re-installing the game?  Sounds like a patch update may have spectacularly failed, hence the game not being properly detected, or you did something really stupid like installing an EP/SP, or CAW, into the base game folder and thus over writing the base game files (plenty of people have been stupid enough to actually do that and then wonder why the game doesn't work).  Have you tried running and playing the game?  Is just CAW that can't find the base game?

[HazelEyes]

No, I used the default installation, the folders are all where they ought to be, and the game runs just fine on its own. I can play, and I can build worlds, but I can't build lots in the new world in-game. It's weird.