How to Import PST into Shared Mailbox Office 365: A Complete Guide

A shared mailbox is a special mailbox that can be accessed and managed by multiple users. This makes it easy for a group of users - with the right permissions - to monitor, receive, and send emails from a common email ID – e.g. support@xyz.com  or info@xyz.com. It is often used to manage customer inquiries, support requests, and other common communications from one email address.

Several organizations import PST files into shared mailbox to keep old emails in one place, centralize historical email, migrate former employee mailbox data, and make important business emails accessible to multiple team members. Read further to know how to import PST into Office 365 shared mailbox. 

Can my mailbox even hold the PST?

It depends on the storage limit of shared mailbox. In the standard license, there is a 50 GB shared mailbox storage limit on Microsoft 365. Therefore, it is pertinent to check the size of your PST file before importing it. If it is huge, then ensure the mailbox – where you’re importing - has enough free space or use an archive mailbox. You can also take additional license to increase the mailbox size.

Decision Table – Which Method should you Use

The comparison table mentioned below helps you to choose the right method for your environment:

Prerequisites for Importing PST into Shared Mailbox on Microsoft 365

You must assign the Mailbox Import Export and Mail Recipients roles to the user account – you’re using for process. These prerequisites are only required for Microsoft Purview Network Upload and Drive Shipping Methods.

Before starting the import:

1. Use a Global Admin or Exchange Admin account. Standard user accounts cannot create import jobs in Microsoft Purview.
2. Verify the shared mailbox already exists and has a valid primary SMTP address such as shared@xyz.com. The import process maps to the SMTP address, not the display name.
3. Assign the Mailbox Import Export role:
   • Open Exchange Admin Center.
   • Go to Roles.
   • Select Admin Roles.
   • Open Organization Management.
   • Go to the Permissions tab.
   • Add Mailbox Import Export.
   • Click Save.
4. Also assign the Mail Recipients role to the same role group. Many administrators miss this second permission, which later causes mailbox mapping failures during import.
5. Wait up to one hour for Microsoft 365 role propagation. Sign out and back into Microsoft Purview after the wait period. If the New import job button is missing or greyed out, role propagation is usually the reason.
6. Ensure the PST file is available locally, on a network share, or ready for Azure upload depending on the method you choose.
7. Verify the PST format:
   • ANSI PST: Outlook 97–2002
   • Unicode PST: Outlook 2003 and later

Both formats are supported, but checking the file type before upload helps avoid compatibility issues.

8. Make sure that Full Access permission to the mailbox is assigned. Without it, import operations often fail due to access validation issues.

9. Make sure to check that your PST file is healthy and not corrupted before starting the import. Corrupted files often cause failed or incomplete imports. You can use SCANPST.exe, if repair is needed.

Best Practices before Importing PST into a Shared Mailbox

Consider the following best practices before importing your PST file: 

• Backup the PST file before import.
• Verify Full Access permissions on the shared mailbox.
• Check mailbox storage.
• Test with a small PST before large datasets.
• Apply date filters to control mailbox growth.
• Validate CSV mappings carefully.
• Review duplicate handling to avoid duplicate messages.

Methods you should Use to Import PST into Shared Mailbox Office 365

Below we have mentioned the methods to Import Outlook data file (.pst) into Shared Mailbox on Office 365.

Method 1: Use Outlook to Import PST into Office 365

If you have full access and permissions to the shared mailbox and your Outlook is connected to the shared mailbox, then you can import the PST file without using the Microsoft 365 admin center.

You can do this by navigating to File > Open & Export > Import/Export. Choose Import from another program or file > Outlook Data File (.pst) and then select the shared mailbox as the destination folder. No admin portal required.  

This approach provides a straightforward way to restore or migrate data without additional administrative steps. It works best for small PST files and occasional imports. If you are managing large PST files, multiple mailbox migrations, or enterprise-scale projects, then you should opt Microsoft recommended methods. Because it provides centralized management and better scalability.

If the shared mailbox is hidden from the Global Address List – GAL – or not auto-mapped to the Outlook profile, it will not appear as a destination during import. In such a case, you can add the shared mailbox manually through File > Add Account before starting. Here’s how to import PST:

1. Verify the shared mailbox appears in the Outlook folder pane.
2. Open Outlook and go to:
   • File
   • Open & Export
   • Import/Export
3. Select:
   • Import from another program or file
   • Click Next
4. Select:
   • Outlook Data File (.pst)
   • Click Next
5. Click Browse and select the PST file.
6. Choose duplicate handling:
   • Replace duplicates
   • Allow duplicates
   • Do not import duplicates (recommended)
7. Expand the shared mailbox folder tree.
8. Then select the correct destination folder. Make sure you choose the shared mailbox — not your personal mailbox.
9. Click Finish.
10. Check the Outlook status bar to monitor the import progress.

Limitations of the Above Method

• It requires Outlook desktop installation
• Not supported in Outlook Web or mobile Outlook
• The Import/Export Wizard may be unavailable in some Outlook configurations – such as – certain Microsoft 365 policies or virtual desktop environments.
• Large PST files may take a considerable amount of time to import.
• It does not provide centralized import-job management, detailed audit reporting, or compliance-focused tracking. 
• It is not ideal for bulk PST migration.

Method 2: Use Network Upload to Import PST into Office 365 Shared Mailbox

You can use Network Upload – (Microsoft Purview) method to import PST files into Shared Office 365. In this method, you can upload a PST file to Azure Blob Storage using AzCopy and map it through a CSV file.

To use this method, you must have the required permissions, including the Mailbox Import Export and Mail Recipients roles. You can access the portal at purview.microsoft.com. Then go to Data lifecycle management > Microsoft 365 > Import. You need the Mailbox Import Export and Mail Recipients roles assigned. Below are the steps:

Note: This import process is managed in Microsoft Purview, not in the Exchange Admin Center. The old Security & Compliance Center has been replaced and now redirects users to Microsoft Purview.

Step 1: Create a new import job

1. Sign in to Microsoft Purview.
2. Go to:
   • Data lifecycle management
   • Microsoft 365

2. • Import
3. Click + New import job.

Step 2: Configure the import job

1. Enter a job name such as:
   • SharedMailbox-PST-May2026

2. Click Next.
3. Select:
   • Upload your data
4. Click Next.

Step 3: Generate the SAS URL

1. Click Show network upload SAS URL.
2. Copy the SAS URL to the clipboard.

Note: Do not close the import job window. You must return to it after uploading the PST files.

Step 4: Upload PST files using AzCopy

• Download AzCopy from Microsoft and extract it to C:\Temp.
• Open Command Prompt and run:
  • cd C:\Temp
    C:Program FilesFSLogixApps
    frx version

This uploads the PST files to Microsoft’s Azure ingestion container.

Step 5: Create the CSV mapping file

• Create a CSV file with the following structure:

Important CSV mapping rules:

• Use the primary SMTP address in the Mailbox column
• Do not use aliases or display names
• Set IsArchive to FALSE
• Set TargetRootFolder to /
• Do not leave TargetRootFolder blank

Leaving the root folder blank can place emails into unexpected folders after import.

Step 6: Upload the mapping CSV

1. Return to the Purview import job page.
2. Enable:
   • “I’m done uploading my files”
   • “I have access to the mapping file”

3. Click Next.
4. Upload the CSV file.

Step 7: Submit the import job

1. Review all settings carefully.
2. Optionally apply a date filter.
3. Click Submit.

Microsoft first analyzes the PST file before starting the import. The analysis stage alone may take several hours.

Method 3: Import PST into Shared Mailbox via Drive Shipping

Drive Shipping is another native method that you use for importing the PST files into Microsoft 365. In this, instead of uploading PSTs over the network, you can store them in an encrypted hard drive and ship it to Microsoft. This approach is useful for bulk imports, large datasets, or when network bandwidth is limited.

Read How to Use Drive Shipping Method to Import PST into Office 365?

Method 4: Import PST into Office 365 Shared Mailbox using Stellar Migrator for Outlook

If you are importing multiple PST files or managing large-scale migrations, then you can use Stellar Migrator for Outlook. Unlike manual methods that require Azure SAS URL configuration or Exchange Admin roles, this tool enables direct import of PST files. Its advanced capabilities helps you to reduce administrative overhead while ensuring accuracy and efficiency. Additionally, it provides features like incremental migration, concurrent processing, and detailed reporting.

When to Use this Tool?

Use this migration tool if:

• You do not have Exchange Admin access
• You need to migrate 10+ PST files
• Multiple shared mailboxes are involved
• Incremental sync is required
• Non-technical staff will run the migration
• You need detailed reporting and dashboard

Here’re the steps to use this tool:

• Purchase the license and install the tool.

• Launch it.
• Create a Job in the Create migration job window.

• Enter the Job name
• Choose the Select whether single or multiple mailboxes have to be migrated option.
• Click Next.
• Click on Select Files on the Select source window.

• Click the Next button.
• Choose the Microsoft 365 option.

• Click Next.
• Now, choose either Auto Registration or Manual Registration.

• Auto Registration – This automatically connects to Microsoft 365 by using Microsoft Azure (Entra ID) credentials.
• Manual Registration – In this, you need to enter the details, such as Email Address, Application (Client) etc.

• Click Validate.
• Now the tool display a list of Target mailboxes.

• The tool will map the mailboxes automatically to Microsoft 365.
• Click on Edit to change the mapping.

• Choose a date filter option.

• Click on Next.
• Choose the folder you want to import.

• Now select the number of mailboxes to be imported simultaneously.

• Review all the parameters before creating the job.

• Click on Finish.
• Now Job created dialog box will be displayed.

• Click OK.
• Click on Start to initiate the process.
• Select Connect to login to the licensing server.
• Once the connection is established, the tool will start migration.

You can track the progress of mailbox migration.

Factors to Consider when Selecting a PST Migration Tool

When selecting a PST to Office 365 migration solution—whether manual or third-party— you should consider the following features: 

1. CSV pre-mapped migration

Admins can pre-create a CSV file to link PSTs to target shared mailboxes. The tool automatically processes the mappings and imports the data into the corresponding mailboxes during the migration process, which helps minimize human effort and the risk of mistakes in the mapping process.

2. Incremental migration

After the initial migration, rerun the job to transfer items that were not migrated during the previous migration attempt. This is useful during staged migrations.

3. Concurrent mailbox processing

Many enterprise migration tools can process multiple mailboxes simultaneously. This parallel processing capability helps reduce the overall migration time and improves efficiency when importing large numbers of PST files.

4. Folder and date filters

Admins can exclude:

• Junk Email
• Deleted Items
• Drafts

They can also import only recent email data.

5. Entra ID app registration

Stellar Migrator for Outlook requires an Entra ID application registration before connecting to Microsoft 365.

Typical setup includes:

• Creating an app registration in Azure
• Assigning permissions such as:
  • Mail.ReadWrite
  • Mail.Send
  • full_access_as_app
• Providing:
  • Tenant ID
  • Client ID
  • Client Secret

Allow 15–20 minutes for setup and permission propagation.

Microsoft Purview vs Specialized PST Migration Tool - A Comparison

The following table compares the Microsoft Purview method and third-party PST migration tool for importing PST files into Office 365 shared mailbox.