Uninstall your most recent EP then download and reinstall the digital version from Origin. Instructions here.
I got the Sims 3 Starter Pack (with Sims 3, Sims 3:Late Night, and Sims 3:High End Loft) and Sims 3 University Life, installed them, but it keeps saying there is no disc. I just got Supernatural and Pets (I thought it was just cause University was the last one I downloaded) and I went to play,the Supernatural icon popped up, and then disappeared and University Life icon pops in its place and it says theres no disc, please help. I have a Mac.
HII!
I have been searching how to play this game for awhile after experiencing the same issue as you. What I tried was uninstalling then installing again. When it prompts you to update the game I hit no. I have no idea what I will be missing out in the update, but as long as I get to play my Sim3 game its kind of worth it.
Please read the stickied disc error thread here - http://answers.ea.com/t5/The-Sims-3/Mac-Disc-Authorisation-No-Disc-Errors/td-p/4882518
