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.\n\nI have tried running Disk Utility First Aid but that didn't help.\n\nI tried running in Safe Mode and that didn't help either.\n\nI tried not including it in iCloud to no avail.\n\nNot sure what else I can try to get Contacts to appear. Can anyone help me? Thanks!