Thunderbird often takes a minute or more to delete received messages, sometimes instant deletion.
Recently update from W7 to W10 but I am not sure when the problem started except it was after upgrade. When I click to delete a received message, sometimes it works normally and the message instantly goes to trash but often it hangs for a minute or two with a message on the top bar saying "Thunderbird is not responding". The hourglass shows on the messages received page whilst this is happening.
Wšykne wótegrona (1)
Do the ones that hang have attachments? Is the TB profile folder correctly added as an exclusion or exception in your antivirus settings?