Checkerboard Skin

Okay, please try this:

1. Drag your whole Sims 4 folder from Document > Electronic Arts to your desktop.
2. Launch Sims 4. You should get no list of mods on launch, and you should have no option to load a previous save. Reset your Options.
3. Start with New to test if your issue recurs in a new game.

Hi,
Lenovo Legion Pro 7 Laptop with Windows 11,
Nvidia 4090 mobile / AMD Ryzen 9 - 7945HX / 1,81 TB of free space

Are you on Mac or PC?

Hi, ...sorry for the delay - was in Vienna the past two days. 

Prior to sending my first message on 22 March, I tried removing all CC/Mods from the Mods folder and, as per Crinrict's suggestions, I also deleted: 
* localthumbcache.package
* lastcrash.txt / lastexception.txt
* avatarcache.package
* houseDescription-client.package
*localsimtexturecache.package

Tried again today with no Mods/CC and the above (once again) deleted: 
-Main save/game has glitches around feet/ankles and darker skin.
- New save has lighter complextion and no glitches.
With all Mods/CC loaded (and above files deleted): 
- Main save/game with glitches.
- New save with no glitches

I still have two saves from the evening before the glitch occured. Would it perhaps make more sense to simply revert back to either of those saves - assuming that those two save do not have the problem causing the glitch?
However, the game is not showing me an option to recover a save from that game - only from the newer "test" save. 
How do I get the older saves from my main game to show?

Thank again!

Make sure to delete the file called localthumbcache after removing the mods folder, and try then editing the broken Sims. 

Hello again, 
I have a strong hunch I may have sent my previous text incorrectly by hitting "Leave a reply" instead of hitting "Reply" directly to you, so that you may not have seen/received it.  If you did already get it, I'm terribly sorry......am definitely not trying to rush you and I appreciate all your assistance. 
************
Hi, thanks for the reply. 
Tried the "vanilla" test and the glitches were 'mostly' gone - for some reason the feet/ankles still have glitches. The skin also appears to be somewhat darker than previously. 
This Sim was originally a NPC spawned by the game, whom I then gave a general 'makeover' (hair, eyebrows, eyelashes, arm- & leg hair, clothes) and added to an existing household. I may have lightened/darkened the skin slightly (don't really remember) with the in-game Skin Tone Menu, but I don't actively use any skin overlays or CC skin tones. Having said that..... I did actually find some skin tone CC in the Mods folder, which I must have accidentally obtained by downloading CC outfits. However, they have all been banned to a folder on my Desktop and the glitches still appear.
By-the-by, all of the NPCs spawned by the game are taken only from my Library (MCCC Population Settings, set to Import Tray Settings 100%) and those Sims were all downloaded from the gallery. 

As mentioned in my first message: with Mods/CC in place, the glitch appears only in my main save/game, but not in either the second or third save/game (also with Mods/CC). As such, I can't get away from the idea that the problem must have something to do with this one particular save/game and not the Mods/CC as such. Perhaps the up-date 'mid-game' threw a wrench into this particular save's coding.........???

Hi, thanks for the reply. 
Tried the "vanilla" test and the glitches were 'mostly' gone - for some reason the feet/ankles still have glitches. The skin also appears to be somewhat darker than previously. 
This Sim was originally a NPC spawned by the game, whom I then gave a general 'makeover' (hair, eyebrows, eyelashes, arm- & leg hair, clothes) and added to an existing household. I may have lightened/darkened the skin slightly (don't really remember) with the in-game Skin Tone Menu, but I don't actively use any skin overlays or CC skin tones. Having said that..... I did actually find some skin tone CC in the Mods folder, which I must have accidentally obtained by downloading CC outfits. However, they have all been banned to a folder on my Desktop and the glitches still appear.
By-the-by, all of the NPCs spawned by the game are taken only from my Library (MCCC Population Settings, set to Import Tray Settings 100%) and those Sims were all downloaded from the gallery. 

As mentioned in my first message: with Mods/CC in place, the glitch appears only in my main save/game, but not in either the second or third save/game (also with Mods/CC). As such, I can't get away from the idea that the problem must have something to do with this one particular save/game and not the Mods/CC as such. Perhaps the up-date 'mid-game' threw a wrench into this particular save's coding.........???

Please do a "vanilla" test:  Drag the Mods folder to the desktop and rename it, delete the file called localthumbcache, open the game to test, and exit without saving.

Missing File - Perry 1