Can we get a definitive set of instructions for everyone? Would save some time.
Everything you download with the launcher goes into a file located in
C:\Users\yourname\Documents\Electronic Arts\The Sims 3\DCCache
It is called dcdb0 (downloaded content database?)
If you delete something from the launcher, this file size does not go down. It will get larger and larger, until your computer goes POP!
I had ninja trousers which i deleted from the launcher. Not only did it keep the space on my computer, but it didn't even remove them from CAS.
This is a shocking peice of programming from EA. Then you have the two other locations the launcher stores each download also.
These ones don't even do anything.I deleted my 100mb dcdb0 and used the 3viewer for everything now.
The only thing I had to use launcher for was Riverview, which had the path name problem unless I used it.
So if you really want to use the launcher for sims or lots, you
could, if remove your dcdb0, install packs, then put the file back afterwards, overwriting. I do this if I want lots from the exchange, and my dcdb0 stays at 14mb.
But thats a shedload of hassle really, best to use 3viewer.
But thats basically the wrongs of the launcher.