Hey there,
I recently installed the Ultimate Collection on my new PC and I'm 100% sure that the Bodyshop was also installed (I made a shortcut to my desktop). After playing I tried to open it. It showed up in my task manager but would disappear after a few minutes. First I deleted the cache files and so on and eventually gave up.

Today I tried to find it under ProgramFile(x86)/Orgin Games/The Sims 2 Ultimate Collection/Fun with Pets/SP9/CSBin but it's gone. Is there any way to install it again without having to reinstall the whole game? How did this even happen?

My guess would be an antivirus program quarantining the file (a false positive when scanning). It's a common problem.

You should be able to fix your game via Origin (you shouldn't need to completely reinstall), though you may want to backup your saved game files first (the ones in Documents/EAGames/...). Then you probably need to whitelist all the Sims files so the antivirus won't touch them.

Here is the M&G Body Shop http://www.simfileshare.net/download/100077/

Use admin rights to unpack it and to install it and you should be able to use it.

The Sims 2 Bodyshop stopped working for me, and I have the last EP installed Mansion and Garden Stuff. I used the exe from the Program Files and also tried the bodyshop from your linked download and it still doesn't work. What can I do to fix it?

^ Have you tried to delete all the cache files?
(accessory, groups, cigen and contentregistry - usually two or more will be present in your Documents/EAgames/TheSims2 folder)

The Bodyshop EXE file should be in the *last EP* CSBin folder, so in the M&G folder (M&G is considered a mini-EP by the game) - but there may be exceptions with collections and the UC.

You may need to run the program in compatibility mode for "Windows XP service pack 3", possibly also as administrator (right-click icon, choose "properties", and "compatibility". If that doesn't work, try one of the other modes (Vista, Win 7 or 8, or XP with different service packs).

I have Windows 7, and run my version (M&G) with XP SP3 mode, not as admin.

I run the one from AL.

I ended up reinstalling Mansion and Garden stuff, and everything runs fine now. Thanks for the tips, I could use those in the future.

The download worked for me, thanks a lot!

I checked my antivirus but it doesn't look like it caused the problem. Anyways, it's solved now!