I recently upgraded the OS to High Sierra 10.13.3 on my mid-2010 iMac and, for the most part, all seems to be working relatively well considering the computer's age. The one real issue I have is that when I open Contacts. The Contacts menu bar appears but the window with the contacts does not. I get the dreaded spinning beach ball and the app has to be force quit. I have tried running Disk Utility First Aid but that didn't help. I tried running in Safe Mode and that didn't help either. I tried not including it in iCloud to no avail. Not sure what else I can try to get Contacts to appear. Can anyone help me? Thanks!