This is a kinda stupid question. I could literally fix this by being careful, but it's really getting annoying... Ctrl+Shift+F, does that shortcut exist? Does it do something? When I do it, my game just instantly crashes with the "The program stopped working and will be shut down" kind of message.
The problem I have with it is that, while I'm building, alternating between Ctrl+Shift+C for the cheats and Shift+F for the quarter tile placement, I sometimes accidentally mix them, and boom, crash. And of course, I lose everything since last time I saved.

So, I was wondering if that shortcut is maybe some feature that for some reason doesn't work in my PC. Something like the Ctrl+Shift+S one to see FPS.
Alternatively, is there any way to change shortcuts for the quarter tile cheat or to open the cheat box?

I don't know if F does anything, but it sounds like it's nothing good.

You can activate quartertile and just leave it on, so you only have to activate it once. That leaves it a bit less likely you'll click anything wrong.

My trick for Ctrl+shift+C is one-handed left. Put your little+ring finger on ctrl+shift and index on C. If you want to go to F with your index finger, you'll have to do an up-maneuver with your hand and curl the two other fingers a bit, so it's harder to do it wrong accidentally, especially if you let your hand rest comfortably on the keyboard (at least on a laptop - been a while since I used a regular keyboard).

I like to turn the quarter tile off because having it activated is a bit annoying when I actually want to put something inside the tile. Specially for objects that have to go in walls.
But I will try that, it sounds like a good way. Let's see if I can get used, I normally use the right hand for the C and the F. Thanks!

And another thing - it can easily be modified to Ringfinger on shift + index on F for quartertile by keping Ring on shift but moving the index finger to F, which kind of automatically makes the little finger move out of the way from the Ctrl-button, which very handily defeats the problem you had.

May take a bit of practice. It also helps to keep the left and right hand on their proper sides of the keyboard (left = anything left of G, right = anything right of H), because it's easier to learn where the keys are, and you don't have to move you hands around so much.

Sounds hard but I'll try. I should really keep each hand in their side, I'm a chaos when typing

So I guess no one else actually tried to do Ctrl+Shift+F.

Ctrl+Shift+F doesn't appear to have any effect on my game. Is it possible that this key combination has been assigned to some other program on your system? (taking screenshots, etc.)

Yes, Ctrl+Shift+F crashed mine too, I'm on Win 10 and play in windowed mode. Not sure why, here's a list of programs that use that key combo but I can't see anything that would explain why Sims 2 crashes!

I doubt it's because of another program. I normally play with no other programs in the background, and doing Ctrl+Shift+F outside the game doesn't do anything either.
I don't play in windowed mode, but Windows 10 too. Must be a Win 10 thing.

According to the Accelerator Key Definitions found in the ui.package Control Shift F is supposed to "Toggle Frame Count Window"
It's part of a set of Key Definitions called "Main Window cheat codes", none of which seem to work.

;;; Sims 2 keyboard accelerators -- Main Window cheat codes

Control Shift F = 0x6818c3c8 "Toggle Frame Count Window"
Control Shift E = 0x0ca03a08 "Activate Edith"
Control Shift R = 0x6ca03a05 "Animation Recorder"
Control Shift M = 0xeca03a43 "Subtract Money Cheat"
Control Alt M = 0xaca03a67 "Add Money Cheat"
Shift B = 0x6ca03a8b "Place Neighborhood Object"
Control U = 0xeca168dc "Show UI Browser"
Shift E = 0x4cb3b26b "Run Demo Effect"
Control X = 0xccb3b274 "Lighting Update"
Control Shift W = 0x0cb3b285 "Toggle Wireframe Mode"
Shift W = 0x2cb3b586 "Toggle Backface Culling Mode"
Alt Return = 0x6ca03a36 "Toggle Full Screen"
Control Shift L = 0x8d8c02ee "Reload Lot"
Control O = 0x2ca03a66 "Show Graphics Options"
Control Shift U = 0x0dab45a0 "Reload UI"