Hi Can you say whether the old and new accounts are POP or IMAP? Also how are you moving folders - drag and drop? Something to try, see if this works for you: - create a new folder in the place you want it in the new account structure. - copy emails into that new folder from the old folder. Try just a few first to see it that works. (You should be able to copy & move up to 1,000 at once but that many may take some time to transfer.)

If your accounts are POP, moving those folders should be OK as it only involves moving them around on your own computer. With IMAP, moving folders into your new account on your computer means those folders need to be created on the IMAP server and the contents uploaded. With a complicated folder structure, there can be difficulties. If your old account was IMAP, and you can no longer connect to the old server, you may have only message titles in Thunderbird's folders, and not the whole email. IMAP fetches the content from the server when you open the email, except if you have chosen to store the message in your local folders. Here's more information about using IMAP if you need it https://support.mozilla.org/en-US/kb/imap-synchronization You may want to consider whether you want to upload a lot of old messages to your new email service - it's all right if you don't have any data limits, but it may take some time to do. Moving the ones that are still part of a current conversation makes sense! Good luck, Agnes

Information here may help you - https://support.mozilla.org/en-US/questions/1267239 and the second of the solutions described here https://support.mozilla.org/en-US/questions/1080813