Can't build over water, build crashes

[araji]

Really hoping someone can shed some light - I've tried to find a solution but to no avail.

The problem is twofold - one, when I try and extend a wall, it tells me I 'can't extend over water' - needless to say, there is no water on the lot.
Two - When I lay down floor tiles, the screen goes blue (aside from the user interface at the bottom of the screen), and then crashes to desktop.

This is very annoying (because I can't do any decent building and my sims keep getting the 'unfinished room' moodlet), and I'm concerned that I'm doing permanent damage to my computer, which is obviously a major concern.

Any suggestions?

[MrsFlynn]

I've had this happen while building a house once or twice a long time ago. It was while building a basement. I'm not exactly sure how I fixed it though other than maybe try building the house in a different town such as Sunset Valley. Save it to the Library and placing it the town you want.

The other thing you might try is working with the building cheats codes, such as Constrainfloorelevation false to see if they might help. I am not familiar with all of them and don't use them.

https://sims.fandom.com/wiki/List_of_build_cheats