It happens suddenly and won't go away without a reinstall.

I go into a lot and begin building, and I notice right away that objects aren't snapping to the grid. They move around freely without locking to anything, as if the grid is not there anymore. There are no cheats active and it's happening on all lots including Maxis lots. I've tried SnapObjectsToGrid True and MoveObjects Off and the usual fixes but nothing's working.

Please help! I don't want to have to reinstall all the packs again >,<!

Have you downloaded anything? Like SeeThem2?
Please go through this FAQ: http://www.sims2wiki.info/wiki.php?...ors_and_Windows

Yes, we have a lot of custom content, including SeeThem2. Would this have anything to do with it?

SeeThem2 installs a startup.cheat. In that file, the cheatcode boolProp snapObjectsToGrid false Is automatically turned on. You need to turn it off to get the grid back. Go through the FAQ i linked you to. It will help you get rid of that cheat.

Thank you very much! We had just installed SeeThem2 today and didn't know that was what it was. We've uninstalled it now, and everything is working right.
Thank you very much Angel!

You're welcome. Next time, make sure to read the instructions in Hacks and other downloads carefully. Then you'll know exactly what they'll do