Having the exact same problem in both of my machines. iMac 5k and MBP @ 2018: I can get the following sequence to reliably happen: Start Xcode 12 and create a new project (or load project) Use any iOS 14 simulator and run the app. Once the simulator starts and completes its startup operations, you’ll get the following crashes: CalendarWidgetExtension, NewsTag, NewsToday2. The app will run. Depending on your app composition, you will probably get more simulator daemon crashes. Terminate the simulator. After a time (15 seconds?) you’ll get another crash: bulletindistributord. You may get other crashes when the simulator closes, but bulletindistributord is always the last. I removed Xcode and /Developer and preferences. Tried with both versions (App Store) and from Dev. downloads. Same behavior. Please, this is driving me crazy...

@rshuston The only workaround I could find: 1) Create a new user in your mac. 2) The problem will be solved as the user library will be different. Which plist is causing the simulator to do this? Unknown for the moment.