I have a complex IMAP folder structure which is a result of the nature of my work, which involves a large amount of email and requires a high degree of organisation. So perhaps a couple of hundred IMAP folders. To head off any 'helpful' suggestions, no, I do not want to change the way I use folders, and no, I don't want to use filters to search for particular emails. For various reasons that is not an effective solution. This type of folder use is normal in my industry and works fine in Outlook within Office 365. However, when I open Thunderbird on a given machine it only syncs mail for the Inbox and not mail already located in all subfolders. I have identified two ways to potentially make Thunderbird check/refresh mail in particular IMAP subfolders. First, I can right click->properties->tick "when getting new messages for this account include this folder". However, this is totally impractical as I would have to do this 200 times and then repeat on three different machines. Second, if I pretend I'm going offline I can go file->Offline->download/sync now and it seems to sync all subfolders. However, I can't get it to do this on startup without me manually activating it, nor can I get it to do this when I click "Get Messages". So is there a way to either assign the first option to ALL folders without having to go through each one individually, or is there a way to force Thunderbird to do a "download/sync now" automatically at start up? Any help greatly appreciated.