
Professional Methods to Migrate Thunderbird Mail to Office 365.
Limitation of Importing Thunderbird Emails to Outlook Office 365 Manually. Step 2: Import EML Files Into Outlook Office 365. Step 1: Download Thunderbird Emails Into Local Drive. Method 1: Import Thunderbird Emails to Office 365. Why does Thunderbird Mail need to be imported into Office 365?. :) Can anyone here beat the gods to it? Any ideas appreciated. I've tried removing my account in Thunderbird, uninstalling, reinstalling: same issue. I've also tried prayer, no results yet. :) Can anyone here beat the gods to it? Any ideas appreciated. The problem is, the user settings in the latest version of the Office 365 Outlook mail app (File/Options/Mail) are extremely limited (one of the many reasons I don't use it), so I can't even check if it's configured properly for sharing IMAP folders: I think all that stuff is now hidden away somewhere in the admin back-end, safely away from us mortals. I've tried pretty much every Thunderbird setting and I increasingly think the problem is caused by office365's servers, probably some new security feature (OAuth2?) that isn't playing well with in Thunderbird's sandbox. The O365 support people here of course believe the issue is with Thunderbird, a setting of some kind. This worked for me too, but it's less than ideal, partly because Outlook comes with a lot of junk folders I don't want and can't delete, mostly because after 20+ good years with Thunderbird I've accumulated a lot of folders that I want to keep but don't need to see every day, for which "unsubscribe" used to be the perfect solution, leaving the folder on the server in case I needed it but getting it off my desk, so to speak. The only solution anyone seems to have found is a workaround, not a fix: Server Settings/Advanced/ uncheck "Show only subscribed folders" will restore all folders. It look like other people have experienced versions of this issue before, especially with Office365: e.g. If I subscribe to all my folders, then close and re-open Thunderbird, I see the folders for a split second and then they disappear, leaving me with only Inbox and Trash. If I right-click my account and select "subscribe," I can see all my folders, and I can check the boxes and select subscribe, but when I click "ok" it doesn't save the checkmark(s). About a week ago, all my folders disappeared from Thunderbird except Inbox and Trash. I'm using the latest version of Thunderbird (78.13.0) to access email in my company's Office365 account.