Sims 3 Loading Bar Stuck

There is no way to increase the amount of RAM that TS3 can use; on Windows the limit is ~3.7 GB, just short of the total 4 GB that any 32-bit application can address. On the Mac version of the game, it's 2 GB. Can we get some specs on the system you are playing on? (processor, RAM, graphics card, hard drive size and space free, how many and which EPs are in play)

There is no NRaas mod that detects corrupt files, I'm guessing you mean either ErrorTrap (does other, different helpful things) or Delphy's Dashboard (not ours and it's a utility not really a mod), but those are just guesses so that one might need some clarification.

There is also no real (hard) limit on a household size if you are using NRaas mods because they allow us to set our own limits or just not have any. How many sims are in this household now? We have had players come to us with households of 30 or 40 sims; in most cases that's just going to be way too much for the game engine to handle under any circumstances. In some cases, it depends on the world, the sims' history, and the player's system, even 15 in one household would be too many.

And if using MasterController, what is the world's town resident population? (On City Hall, NRaas > MC > Demographics > Population > ("X" to dismiss the filter)

But it should be said that corruption is not an all or nothing thing, it can set in slowly and build over time making an ongoing game less and less playable. The mods that work pretty hard to help prevent that are Overwatch, ErrorTrap, Register, Traffic, to an extent GoHere, Traveler if any form of world travel is in play, and MasterController for its Reset Everything command on the Town menu at City Hall. Other mods may be adding to the stress over time rather than help relieving it; any what seem to be hard-hitting script or core mods from other sources?
https://www.nraas.net/community/TIPS-FOR-BETTER-GAME-PERFORMANCE

If a game with a smaller active household loads up normally, and a newly started test game does as well, then we do kind of have to conclude that it's something not yet identified or confirmed with the save in question, the one with the large active household, that for some reason or another is causing the problem.

@SimCat68 When someone is requesting technical help I think the first step should always be to provide a fresh DxDiag report on the computer in question.

How to gather information on your PC using DxDiag

After the report is finished, upload it to Pastebin and put a link to it in your next comment here.