If you have deleted your Collections files, you can get them back without reinstalling all your EPs.
Each set of Eaxis collection files is in the appropriate stuff pack or EP folder eg C: \Program Files\EA GAMES\The Sims 2 expansion or stuff pack name\TSData\Res\UserData\Collections
COPY and paste DO NOT MOVE! into the Collections folder of your game files;
ie \My Documents\EA Games\The Sims 2\Collections
Sita January 30, 2019