Update to Catalina, Mail using excessive memory, cannot use Mail

Hello jeannette147! 

Thanks for reaching out to the Apple Support Communities. I understand that the Mail app is crashing on your 2017 MacBook Air since updating to macOS Catalina. I know how important it is that I can access my email, and have some troubleshooting steps for you to try. 

1 - Quit the Mail app by selecting Command + Q or using Mail > Quit Mail from the menu bar. Once it’s closed, restart your MacBook Air: Go to the Apple menu in the top left corner of your screen > Restart. 

2 - Hold down the Shift key on the left side of the keyboard and click on the Mail app. Once it’s bouncing in the dock you can release the Shift key. This will allow the Mail app to start up by bypassing the saved state the app was in last. 

3 - If the issue persists, restart in safe mode and test again: Use safe mode to isolate issues with your Mac. 

4 - If still occurring in safe mode, you’ll need to create a new user and test it out again. This article will show you how: How to test an issue in another user account on your Mac.

If you still are experiencing the same performance issues with the Mail app, or if you’re seeing any error messages, let us know.