O365 migration

Question

Hello,

I'm planning to activate O365 tenant for one AD domain (50 users) and migrate 50 mailboxes to O365.

Current environment:

1 SBS 2008 server with Exchange 2007 on it.
Exchange has POP3 connector to connect to ISPhttps://techcommunity.microsoft.com/t5/windows-server-essentials-and/sbs-2008-introducing-the-pop3-connector/ba-p/397066 and download e-mail.
Mail flow(mx record) is directed to ISP and ISP is a SMTP smarthost for sending and Exchange 2007 on-prem via POP3 connector downloads mail locally for all 50 users.
Exchange 2007 on-prem is not published outside and have not 3rd party cert and customer want to decomission Exchange.

What I plan to do to migrate users to O365:

Activate O365 for this domain,create 50 users in cloud without AD connect (no SSO,users will have 2 accounts,on prem AD and azure AD),move mail flow(mx) from ISP to O365,add O365 mailboxes to this 50 users outlook so thay have 2 e-mail accounts in outlook(o365 and on-prem) and than export .pst from old on-prem exchange and import to O365 account and decomission Exchange 2007 on -prem.

Any advice,suggestion?

p.s.
The reason to do this way is that I need to decomission Exchange on-prem.AADConnect is not supported if I plan to decomission Exchange on-prem.
Other reasons to do this way is that exchange on-prem is not publish outside and has no backup and has pop3 connector to ISP and it is SBS server and it is Exchange 2007 and SBS server is risky to restart because windows sbs systems file are corrupted...and many other reasons.
I decided to configure tenant,redirect mail flow and import .pst to tenant.

Answer 1

Hi @fsdg ,
Considering your situation, there are only fifty user mailboxes, the environment is not published and there is no third-party certificate. I think export the mailbox to .pst file and import the .pst file to migration is achievable.

We could try to export and import by using Import/Export feature in Outlook client. Accoridng to my test, I export a mailbox in on-premises Exchange server to .pst file, and then import the .pst file to the mailbox in Exchange online. I can successfully see the mail information in the on-premises mailbox. For better migration, before export the mailbox to .pst file, please set up the Outlook client to "Online mode" to make sure that .pst file include complete mailbox data.

In addition, we could also use the Import service in the Security & Compliance Center to quickly bulk-import PST files to Exchange Online mailboxes in your organization.
For more information please refer to: Overview of importing your organization's PST files

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