help Migrate Thunderbird mails to Exchange

[GeneralShagg]

The problem

So I need to migrate some mailboxes from Thunderbird to Exchange 365.

Thunderbird doesn't use the same file format as Outlook or other email clients, so I need to convert them to be able to import these emails.

We currently have a POP3 mail server, in which we do not store emails received for more than 2 days. All emails are stored locally on users' PCs. So I can't just install another client to download and export the emails.

 

The solutions

• Export the files manually as an EML file and import them into the Outlook application so that they can be synchronized with Exchange 365.
  • This solution is not viable because one of the users has more than 160 GB of email. I would take years to do it this way.
• Using software to automatically migrate all emails from Thunderbird to Outlook/Exchange.
  • In this way, it could work, even if I have to pay software, I will save a lot of time.
    • I would need some recommendations because there are a lot of software... (SysTools, Aryson MBOX migrator, DRS MBOX to PST converter,...)

 

My questions

• First question is that Exchange 365 does not offer a mailbox that can store 160 GB of mail.
  • Exchange Plan 2 can store up to 100GB, but on the Microsoft Exchange Limits page, I can archive up to 1.5TB3 in emails.
    • As I understand it, I should be able to import all his emails and archive most of them and he could access them whenever and wherever he wants.
• Second question, for software recommendation, it would help if there was one that could do Thunderbird to Exchange 365 and Outlook to Exchange 365 migration.
• Finally, do you have any advice, recommendations or anything that could help me in this process? This is pretty much the first time I transfert this quantity of mailboxes (~20)