My sims 3 64 bit stuck on the loading screen

@classicacosta  As a test, please try loading a new save in Sunset Valley and let me know whether it works.  Please also let me know whether you use mods or custom content.  It's fine if you do, but that means troubleshooting might be a bit more complicated.  For example, I'd like to know whether you've placed any cc items in the new version of SV.

Ok, so I eventually was able to get into the Sunset Valley Updated save that I made. But I still encountered some problems and that is that my screen started glitching, I've added photos! I do have custom content and mods in my game. I don't have any cc items in SV Updated like cc buildings and stuff like that. But I do have cc in my game in general but just cars from freshprincecreations all my mods are nrass mods. 

I'm honestly not sure what to do. But thank you so much puzzle addict! 

@classicacosta  The graphics glitch in the screenshot you did attach is likely caused by custom content.  The issue could be a default skin or a clothing item; try taking your sim into CAS and changing only the clothing and hair (all items in the everyday outfit), or only the skin (both swatch and slider position).  In either case, use only EA-made items.  You can "save as" and rename the save for your tests: the original will remain intact under its current name, and you can experiment on the new copy.

If this sim doesn't have any custom content, not even a default replacement skin you're using, it's also theoretically possible that the game engine isn't rendering the skin color correctly.  In other situations, the screen can flash red for no apparent reason, or certain houses can appear solid red, although all the reports I've seen are for buildings and not sims.

Since you're getting flashing too, please describe it in more detail, or take a video if you can.  Here's how to do it with built-in tools:

https://support.apple.com/en-us/HT208721

Please also attach your deviceconfig.log to a post; it's in Documents > Electronic Arts > The Sims 3.  (You'll need to manually open the folders; the file won't show up in a search.)  You can delete your user and computer names, about 25 lines down, but there's nothing else in that file that can identify you.

Hi, so now I can't even get into my saved game I have. It's just a black screen when I enter the loading screen of the saved game. 

Update: I was able to get into another saved game of mine that I have had problems with. With the current saved game I'm trying to enter I'm still stuck on the loading screen, it's not turning completely back anymore but it's still stuck on the loading screen.

@classicacosta  Is this with mods and custom content removed, or still present?  You can also try loading the game's automatic backup save, which you'll see in ... The Sims 3 > Saves.  The folder with your save name plus a .backup extension is the backup; rename it and delete the .backup part (e.g. MySaveName1.sims3), and it will be available to load from the Main Menu.

So I still have mods and custom content in my game, I'll try the backup save method and get back to you! Thank you so much!

@classicacosta  Please start with a clean user folder, with no mods or custom content.  I know you want to keep your mods and cc, but it's easier to go piecemeal at this point.  Move your entire Sims 4 folder out of Documents > Electronic Arts and onto your desktop, open the launcher to spawn a clean folder, and try loading a new save, just to make sure it still works.  Do not add any mods or cc yet.

If the new save loads, copy the backup version of your problem save to the new folder and see whether it loads.  Don't add any other content unless this "SV updated" takes place in a different version of Sunset Valley, in which case install only that world, nothing else*.  Let me know whether this works, and we can go from there.

If you happen to use AwesomeMod, you'd need to install it too, because saves that have been played with it may not work if it's removed without the proper procedure.  But please try at least once without any other content.