I don't know what is causing this, I tried updating the thumbnail cache, shuffling around some CC, all to no avail. I thought it was those first 4 CC terrains that are pink but getting rid of them didn't help.

Have you tried Ctrl-Right Click on the affected thumbnails?

Deleting the thumbnail caches should reset the files. Ctrl-Right-clicking resets one by one and shouldn't be needed if the full cache file has regenerated (but still could be worth a try).

Do you have pink-flashing elsewhere, or just in the catalog?

Which game version do you have - if NOT the Legacy version or Mac version, have you done the 4GB patch?

Have you used hte Graphic Rules Maker at any point? (Make sure you used the proper settings).

If you open your "...\Documents\EA Games\The Sims™ 2 Ultimate Collection\Logs" folder (or the closest path similar, if you've got Legacy/other version), and open the "(computername)-config-log" file, what does it say for "Memory", "free memory, and "Texture memory"?
(alternatively, copy/paste the info ABOVE "Global properties" (the info below isn't necessary).

Yes


I use Legacy, not sure the log file will be useful in this case since all the info is wrong by default, but I attached it anyway

I'm not sure what the Legacy file is supposed to read, but I have a feeling it's not meant to be 0mb. The Legacy game should already be set up for 4GB, so it should at the very least read 4096MB for the two first ones.

It's supposed to read 0, I'm also not playing on Windows NT (from the 90s lol) as it states either and it's not the year 2 million or the month of February. It doesn't list the correct GPU even though the game detects it. That whole portion of the file is like that with Legacy. And the 4GB patch is useless for Legacy since the game was fixed to already use the max amount of RAM that it can.