Downloaded Update. Now, Anki App doesn't open

I think “the application is not responding” is a Windows error message, so I presume you’re paraphrasing? Things you could try on a Mac:

  • Starting Anki while holding down the shift key
  • While Anki is closed, backing up your data folder, and then renaming prefs21.db to something else
  • Changing the video driver
  • Checking the console output and pasting it here

https://docs.ankiweb.net/files.html#file-locations
https://docs.ankiweb.net/platform/mac/display-issues.html
https://addon-docs.ankiweb.net/console-output.html#macos