Since July 31, 2020 all my IMAP-based WLM 2012 messages have been displaying the following: 

Windows Live Mail encountered an unexpected problem while displaying this message. Check your computer for low memory or low disk space and try again.

Also get the following error message now as well:

Unable to send or receive messages for the D-------- account. Header download for the 'Trash' folder did not complete. Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity.

Server Response: The server did not respond to this IMAP command before the connection was terminated.

Server: 'imap.comcast.net'

Windows Live Mail Error ID: 0x800CCC0F

Protocol: IMAP

Port: 993

Secure(SSL): Yes

I have already ran Windows Essential repair and also repaired & defragged the Mail.MSMessageStore database