I had this bug, or something very similar to it, about a year(ish) ago. Sims would just keep doing whatever they were doing at the time. Read forever, pee forever, stand at the fridge forever. Nothing could make them budge apart from a hard reset, and that lasted a few seconds.
It was at least partly reproducible, I was able to trigger it by ordering pizza for example, and it seemed to occur more often when guests were visiting. Otherwise it was largely random, occurring both in huge houses with many sims staggering under the weight of their giant inventories and in two-person hovels in another neighbourhood. It followed empty-inventory sims to work in the hospital, it struck Landgraab and Goth alike.
Though interestingly, townies continued to wander about outside as normal.
No length of pausing brought them back (and I pause very frequently in normal play anyway, only run the clock fast when everyone's asleep or at work), no amount of waiting caused anything except starvation and woe.
There were no fixes at the time, so I turned off the game to wait for a patch.
Decided to get back into it this week, lo and behold, nothing has changed. That's, to put it mildly, disappointing.
And then I hear that there was a mod to fix the issue, which an official patch broke a few weeks ago.
Astonishing. Official patching that makes the game worse.
Anyway, I'm as keen as the next person to get this resolved, here's what I can provide:
CPU: Intel Core i5-3570K
OS: Windows 10
RAM: 8GB
GPU: Nvidia GeForce GTX 780
HD where the game is installed: 450GB free
HD where the game keeps its screenshots, mods and the like for some reason: 92Gb free
- How big is your save game: I'm not sure how to measure this but most of the files in that folder are 3.2 to 3.7KB.
- Does the issue also occur on a new save for testing purposes: Yes.
I also use a bunch of mods, most of which are for hairstyles and the like. No script mods. I run the game at max settings and I'm not interested in turning them down. Reinstalling and resetting did nothing.