In case you weren't aware, new Origin updates are very capable of breaking or impairing Sims 2 Ultimate Collection:

http://www.modthesims.info/showthread.php?t=624654

Origin has a new "mandatory" update that is so mandatory Origin won't even load in Offline mode. Meaning I cannot open TS2UC.

Is there any way I can get around this?

I just opened Sims 2 UC and it didn't make me update or even open Origin.

pre-infested executable is the one of most useful solutions;
also - you may try to temporary disconnect (just unplug the cable or disable wifi) and allow Origin "go online", the updater will fail but the main executable should then load properly (if it's not broken) in "offline mode". It worked, but I cannot guarantee it's still working, sadly.

It is still working, online too.

I'm probably gonna get hated for this but just use a No-CD crack, especially if using origin has the chance to break your entire game.

I'm not gonna link one but you should be able to find one pretty easily.

Does it load if your computer is not connected to the internet, as ElaineNualla suggested? I think we all sometimes forget that we can just disconnect from the internet.
Alternatively, I don't know if we're discussing this here, but my game was never connected to the internet after UC was installed. I just changed the shortcut to point to the exe file instead of the origin-al one, so mine never updated. I did recently experiment with swapping one of the newer Origin-patched exe files with my older one, and it worked just fine.

ahem.....(George) p.m. me if you want a link.

What?? I didn't say anything!

I tried the Offline/no wifi mode and Sims 2 won't open at all. I get a "origin had trouble loading this page"

I live in a hurricane-prone area, so I have great interest in not having to use the internet. There is a work around, but we can't talk about it on here. P.m. if you want a link.