Toggling the status using the icon that looks like two adjacent PCs in the lower left corner of the main window or using file -> offline -> work offline does not do that on my PC. That depends upon how you switch to working offline. ' Thunderbird even asks to download e-mail before going offline' Unfortunately, the offline folders can not be used as a cache like Apple Mail or Outlook supports. They are stored as mbox files just like POP accounts do.
However, your synchronization & storage settings by default are configured to have Thunderbird automatically download a copy of all of your mail folders as 'offline folders'. In fact they normally fetch a message from the server every time you open it (unless you open the same message twice in a row). IMAP accounts store messages in remote folders on the mail server. If you delete a message in webmail or using the IMAP account when Thunderbird synchronizes the account it will delete the same message in the corresponding offline folder. When you are in online mode you view the contents of the remote folder, and when you are in offline mode you view the contents of the corresponding offline folder (if it exists). ' why would I have a 275MB INBOX file for my Hotmail account if all the e-mails were only on the server?' My Outlook IMAP account suddenly stopped working. According to and both the Hotmail and Outlook mail servers are having problems.
