Best method for mass uploading local emails to server?
Hello
What would be the best method for uploading many local messages back to the server? I have about 9000 messages in my Thunderbird local inbox and about 3700 in my local sent folders that I'd like to re-upload back to the server. 6.5GB in total.
I've got an IMAP Outlook account (with an @live.com email address) with emails going back about 13 years. Previously, I used ImportExportTools NG to download all emails from 2010 - 2019 to my local folders and deleted them from the server to free up space. Recently we bought a 100GB cloud storage plan, so now I'd like to re-upload those old emails back to the server. What's the best method?
Everything I've read online says that trying to upload a lot of emails at once will cause errors, some messages will fail to upload but you might not know which ones, and other such issues. I'd like to avoid that headache so I haven't tried to upload a huge chunk yet.