Migrate Exchange 2010 Mailbox to Office 365 Step by Step

Migrate Exchange 2010 Mailbox to Office 365 Step by Step

Exchange Server 2010 reached its end of life on January 14, 2020, which was extended till October 13, 2020, to give more time to customers and administrators to finish the migration. Although Exchange 2010 will continue to run after its end of life, it won’t receive new security updates, bug fixes, and Microsoft support. Thus, it’s critical to migrate mailboxes from Exchange 2010 to a newer version or Office 365.

Office 365 is more reliable and secure than Exchange on-premises, which is prone to malicious attacks and failure due to power outages or hardware issues. Exchange on-premises servers were recently attacked and exploited by a threat group called HAFNIUM, which compromised more than 30,000 servers worldwide. Thus, it makes more sense to migrate Exchange 2010 to Office 365, as it is unaffected by such attacks.

Below we discuss the different methods to help you migrate Exchange 2010 mailboxes to Office 365.

Methods to Migrate Exchange 2010 Mailbox to Office365

Based on the number of mailboxes you need to migrate to Office 365, you may choose between the three native Exchange 2010 to Office 365 migration methods.

Method 1: Cutover Migration

Cutover migration allows you to migrate a maximum of 2000 Exchange mailboxes to Microsoft Office 365. However, the method is recommended to migrate 150 mailboxes as it takes significant time that can lead to extended downtime.

Method 2: Hybrid Deployment

Hybrid Deployment or Migration allows you to migrate Exchange 2010 mailboxes to Office 365 progressively. Hybrid migration allows an organization to maintain their on-premises Exchange while migrating the Exchange 2010 mailboxes to Office 365 simultaneously. This helps Exchange administrators to manage the Active Directory (AD) on their on-premises Exchange and allows their users to access and use services and mailboxes on Office 365.

Method 3: PST Upload

In this manual method, you need to export the Exchange 2010 mailbox to PST via Exchange Management Shell (EMS) or Exchange Admin Center (EAC) and then upload the PST to Office 365. Similar to Cutover and Hybrid Migration, this method also requires you to perform multiple manual steps to migrate Exchange 2010 mailbox to Office 365, which are as follow,

Step 1: Assign Mailbox Import Export Permission

Before you can export Exchange 2010 mailbox to PST, you must assign the Mailbox Import Export role to the user account. This role is not assigned by default to any user, including the administrator. To assign the Mailbox Import Export role, you can use the EAC or EMS command, which is as follow,

New-ManagementRoleAssignment –Role “Mailbox Import Export” –User <USERNAME>

New-ManagementRoleAssignment –Role “Mailbox Import Export” –User Administrator

After executing the command, restart EMS and follow the next step.

Step 2: Export Exchange 2010 Mailbox to PST

To export mailboxes from Exchange 2010 to PST file, you can use EAC or EMS. As EAC provides limited export options, you can use the New-MailboxExportRequest PowerShell cmdlet in EMS to export single or multiple mailboxes from Exchange 2010 database to PST.

To create a mailbox export request, execute following command in EMS

New-MailboxExportRequest -Mailbox <MailboxName> -FilePath <UNC PATH>

New-MailboxExportRequest -Mailbox John.C -FilePath \MBOX01.pst

This will create a mailbox export request. You can check the status of the request by using the Get-MailboxExportRequest cmdlet.

Get-MailboxExportRequest -Name MailboxExport | fl

Check out New-MailboxExportRequest guide to know more about the New-MailboxExportRequest cmdlet and use it to create requests to export specific or multiple mailboxes and Archive Mailbox to PST.

Step 3: Upload PST to Office 365

It’s not as simple as it sounds. Uploading PST to Office 365 requires you to assign the Mailbox Import Export role to the user account you will be using to upload the PST to Office 365. You can use the EAC or EMS to assign the role.

Then follow these steps to upload the PST to Office 365.

  • In Office 365 Admin Center, click on Compliance and then navigate ‘Information governance> Import.’


  • Click ‘Import PST Files’ and click the New Import Job
  • Enter a job name and click ‘Next
  • Click Upload Your Data and then click Next.
  • Click Show Network Upload SAS URL. Copy the SAS URL in your Notepad or any text editor.
  • Download and install the Azure Storage Explorer tool on your system.


  • After installation, launch the Azure Storage Explorer. Right-click on Storage Accounts and select Connect Azure storage…
  • Select Use a shared access signature (SAS) URI and click ‘Next.
  • Paste the SAS URI you copied earlier to the URI section and click ‘Next.’
  • Click ‘Connect’


  • Next, click ‘Upload> Upload Files…’
  • Click on … icon and browse the PST file you exported via New-MailboxExportRequest PowerShell cmdlet or EAC. Select a Destination directory on your Office 365 storage and click ‘’
  • After uploading the PST file, create a CSV file on your PC, as shown below, to map the PST file to the Office 365 mailbox account.



  • Go back to the Import data window and check the two checkboxes. Click Next.
  • Click Select Mapping file and upload the CSV file. You may click Validate to verify the file and then click Save.
  • Click ‘Close’ and then click ‘Refresh.’


  • Double-click on the job name and click on the ‘Import to Office 365’ button


  • Select ‘No, I want to import everything’ and then click ‘Next.’
  • Click ‘Import data’ to complete the PST import process.


This completes the migration of the Exchange 2010 mailbox to Office 365. Repeat the steps to import more mailboxes.


Although these native methods can help you migrate Exchange 2010 mailbox to Office 365, they require a lot of time and effort. Plus, the migration may not be smooth, and you may encounter roadblocks that can cause further downtime and data loss. Also, these methods use PowerShell and EMS cmdlets, which require you to have some level of proficiency and expertise.

A much more straightforward, seamless, and direct way to migrate Exchange 2010 mailboxes to Office 365 is to use an Exchange to Office 365 migration tool, such as Stellar Converter for EDB. The EDB to PST software can export the mailboxes from Exchange 2010 offline database file (.EDB) directly to Office 365. All you need is the credentials of your Office 365 account. You can export single or multiple mailboxes simultaneously to Office 365, which saves time. Also, anyone with little to no expertise can use the software to migrate Exchange 2010 mailbox to Office 365.

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