Catalina Mail super slow when composing new emails?

More people experience slow emails on Catalina?

Running a MacPro with 64 Gb RAM and its slow like fek. Especially when typing emails feels very laggy.

Running latest version 10.15.2 and I have the check spell why you type is off. Got 8 mailboxes of which one is a Office 360. Under settings iCloud, I switched off mail (FWIW). Plenty of diskspace (> 1.4 TB free).

I also tried a reboot and PRAM reset.

Anybody got a clue?

1. Open up a Finder app session
2. You will need access to your User library
3. Go to Folder Containers > com.apple.mail > Data > Library > Saved Application State Go > Go To Folder and type in as shown above.
4. Move com.apple.mail.savedState to Trash Move this folder to the trash
5. Next, in Finder app, press down the Option key and click on Go at the top of the menu
6. Type in ~/Library/Containers
7. Drag com.apple.mail and com.apple.MailServiceAgent out to your desktop

8. Similarly, remove the envelope files from ~/Library/Mail/MailData and drag them to trash

   • Envelope Index

   • Envelope Index-shm

   • Envelope Index-wal

9. Empty your Trash and Restart your Mac

If your Mail works without hiccups, you can move the files from your desktop into Trash ( file from step 8 above).