Duplicate emails displayed

I’ve dropped the database after deleting accounts and re-added them. Still occurs, with emails duplicating. No forwarding rules to account for duplications.

Advice, pointers to what worked for other people welcome and appreciated.

I have exactly the same issue:

  • setup only one mail account
  • clicking on one email will display two duplicate emails in the mail-viewer

FYI: My solution was to remove and add the email account again.