Backup or Archive all Microsoft 365 Exchange Online Mailboxes to PST files at once using PST Migration Tool from ManageEngine
Issue
You need to backup a bunch, if not all, mailboxes from your Microsoft 365 Tenant at once and eDiscovery export to PST method does not suits you.
Solution
In this article we will describe the usage of a software called PST Migration Tool from ManageEngine.
Prerequisites
Please install Active Directory Free Tools at the end. You will need to provide an email address to get the installer.
Hardware
A dedicated computer or virtual machine with enough storage to get all your emails stored.
Do not run on Microsoft Exchange server machine.
Software
Microsoft Exchange Web Services Managed API 2.2 : https://www.microsoft.com/en-us/download/details.aspx?id=42951
Microsoft Exchange Server MAPI Client and Collaboration Data Objects : https://www.microsoft.com/en-us/download/details.aspx?id=42040
Microsoft Outlook (32 bits) : This is required as the Export tool will only create 2GB PST files if Outlook is not on the machine. Outlook 32 bits is required as the Free Tools are also 32 bits applications.
ManageEngine Active Directory Free Tools : https://www.manageengine.com/products/free-windows-active-directory-tools/free-active-directory-tools-index.html
Mailbox Permissions
You will need to access the mailboxes folder from an administrative account. You can do that by either using impersonation or granting the account full access on every mailboxes.
Disable MFA
You will probably have to disable MFA on the main account that access your tenant for a moment to authenticate in this application.
Process
Run the Ad Tools : Start -> Start Tools
You may receive the following message upon startup. Now worries, this is due to the fact your machine is not part of a domain. We won’t need Active Directory tools so you can ignore this by clicking Continue.
In the main windows, click on Other Tools, scroll down and click on PST Migration Tool.
Make sure you have selected Exchange Online under Environment, enter the user’s credentials and click Add.
Then you should see your account in the Account list.
Go to Export PST tab and click Select under Select Mailboxes. (Should you have added different identities, please select the correct Tenant and Account above)
Wait until the tool retrieves all accessible mailboxes, select the ones you want to export and click Select.
Select the folder you want to save the PST files into under Storage Path
Select the folder and press OK
Select how the filename will be set for each PST file. I prefer Email Address. Then click Next.
Review your selection and click Export.
Sit tight and wait for process to complete.
Remember : If your PST files are not exceeding 2GB, it means the software did not detect Microsoft Outlook 32bits.
Source
I made it myself. Exclusive content. 🙂