Why IMAP emails do not download automatically?
Going back many versions now I have noticed Thunderbird fails to download new email messages as they arrive on the mail server inbox or junk folders, until now I have lived with it but I need a solution. If I click on any folder like Inbox or Junk the most recent messages are downloaded for that folder. I have set Server Setting to: 1)Check for new messages at startup (which seems to work) 2) Allow immediate server notifications when new messages arrive (does not seem to work) In the past IMAP did not require periodic checking for new messages, as the server received them Thunderbird displayed them, so I have not set Check for new messages every X minutes. In the past many mail servers did not like auto checking more frequently than every 15mins (not sure if this still applies these days). Are there any other mail settings in Thunderbird that may prevent Auto Download of new messages as they arrive. I have the latest Thunderbird ie 115.10.1 (32 bit) Supernova I have four mail account all on different servers same problem with all. Last time I used MSOutlook (which I don't use anymore) it worked fine so I'm leaning toward this being a Thunderbird issue. Windows firewall set to allow Thunderbird Router set for DMZ to machine just in case. ;>) Am i missing a new Thunderbird setting I cannot find?
Opaite Mbohovái (1)
IMAP has always required manual intervention (timed fetching) for the vast majority of new mail. When IMAP was first released, it was the only way to get new mail and even now it renews the login that is used to push out mail using IDLE.
The IMAP Idle command allows the server to push new mail. In practice this is sometimes only new mail in the inbox, so server side filtering can mess things up, depending on the server implementation.
Thunderbird does not routinely poll the junk/spam or deleted/trash folders and that is a default set by developers as interruptions notifying of getting spam is hardly a good thing. You can modify that and include the folder by right clicking it, selecting properties and checking the box to include the folder when getting mail.
Note that there have been issues with mail more than two levels below the root folder, I did not follow the bugs and I am not sure if they are fixed. But from what you have offered I does not sound like your issue.
Note that when there is an antivirus product scanning mail it sits between the mail client (Thunderbird) and the server pretending to be either the server to Thunderbird or a client to the server. This greatly increases the chance of failures, so disable that if it exists to see if it may be a factor. I can see an antivirus product simply dropping the ball completely with server initiated data downloads.