PST to Office 365 Migration Step-by-Step Guide

Before importing PST data, prepare the target Microsoft 365 tenant and confirm that the required destination mailboxes are ready.

• Review available network capacity and Microsoft 365 migration performance considerations. See Microsoft 365 network and migration planning and migration performance factors and best practices.
• Prepare the target Microsoft 365 tenant and required administrative access. See the Microsoft 365 tenant roadmap.
• Make sure each destination user that requires an Exchange Online mailbox has an appropriate Microsoft 365 license. Compare Microsoft 365 business plans and Microsoft 365 enterprise plans.
• Create the required users and destination mailboxes and assign suitable Microsoft 365 licenses.

   Add users in Microsoft 365

   Add several users at the same time

   Assign Microsoft 365 licenses

• If selected PST folders will be mapped to Microsoft 365 Public Folders, create and configure the required Public Folder hierarchy and permissions on the target before migration.

   Create Microsoft 365 Public Folders and assign permissions

• If PST data will be migrated to an Online Archive mailbox, enable the archive for the target user before mapping. See steps to enable Online Archive in Microsoft 365.
• If this PST import is part of a broader mail-system cutover, add and verify the required custom domain in Microsoft 365 and plan the DNS changes separately. Importing PST data by itself does not require changing your MX record.

   See Microsoft 365 DNS record guidance.

• Review Exchange Online message-size limits before migration. Microsoft documents a 150 MB migration/general message-size ceiling for supported scenarios, while tenant, mailbox, client, and other service limits can be lower depending on configuration.

   See Exchange Online limits.

• • Step 1: Download EdbMails PST to Office 365 migration tool

    • Download and install the EdbMails application on your computer.

      

    • See the EdbMails PST system requirements for PST to Office 365 migration.
    • Launch the EdbMails application.
    • Enter the email address & password and click ‘Login’ or ‘Start Your Free Trial’.

      

    • Select ‘Outlook PST Recovery and Migration'

      

    • Select ‘PST to Office 365’.

      

    • You can either keep the default job name or click the ‘New Job’ button to change the job name.

      

  • Step 2: Select the offline PST file

    • Click ‘Browse for PST file’.

      

    • Select the offline PST file from your computer drive, then click the ‘Next’ button to continue. You can also use an accessible PST from a network location, provided the computer running EdbMails has reliable access to the source file.

      

  • Step 3: Preview and select the mailbox

    • EdbMails scans the PST and builds a preview of mailbox data it can read. If the PST is damaged, recovery depends on the data that remains present and readable in the source file.

      

    • After scanning, the available folder structure appears in the left pane. Expand folders to preview supported emails, attachments, contacts, calendars, tasks, notes, journals, and other mailbox items before migration.
    • Select the required mailboxes / folders and click the ‘Next’ button.

      

    • EdbMails provides filtering options to narrow the migration scope. For example, use date filters to migrate only items within a required date range.

       PST to Office 365 migration filter settings

  • Step 4: Connect to the target Microsoft 365 tenant

    • Click the ‘Add New’ button to create a connection to the target Microsoft 365 tenant. To reuse a previous connection, select it from the connection list and click ‘Connect’.

      

    • Select the required connection options and click the ‘Next’ button.

      

    • Select one of the available authentication methods and click ‘Login’ to continue.

       Connect to Microsoft 365 using modern authentication

      

    • Complete authentication on the Microsoft sign-in page.

      

    • Select one of the methods to load the mailboxes. You can also load the mailboxes using a CSV file.

      

  • Step 5: Map source and target mailboxes

    • Choose the required mailbox mapping option

      

    • If you choose the supported automatic mailbox-creation workflow and the connected account has the required permissions, EdbMails can create target Microsoft 365 users/mailboxes and assign available licenses.

       Learn more about automatic mailbox creation and licensing.

    • EdbMails can automatically map source and target mailboxes when identifiers match. Review every mapping and manually change the target where required before starting migration.

      

  • Step 6: Start PST to Office 365 migration

    • Click ‘Settings’ to apply the required migration filters. For example, use a date range to migrate only items received within a specific period and exclude data that is outside the migration scope.

        Date filter settings for PST to Office 365 migration

    • Click the 'Start Migration’ button to initiate the migration process.

      

    • Monitor the migration in the progress view. You can pause or resume the operation using the supported controls. Microsoft 365 throttling or transient service conditions can affect throughput, so large migrations can require additional time or retries.

      

    • Review the migrated folders and item counts in the EdbMails migration log report.
    • Sign in to the target Microsoft 365 mailbox and verify representative messages, attachments, contacts, calendars, folders, and other important data.

• Step 1: Verify the migrated mailbox data

  Review the EdbMails migration log and validate important folders, messages, attachments, contacts, calendars, and item counts in Microsoft 365. Keep the source PST until the migration output has been verified.

• Step 2: Update DNS only when this is part of a broader mail-flow cutover

  A PST import alone does not require changing MX or Autodiscover records. If the PST migration is part of moving your organization's active mail service to Microsoft 365, perform the required Microsoft 365 DNS changes as part of that separate cutover plan.

• Step 3: Reconfigure Outlook only if required

  Importing PST data does not automatically require a new Outlook profile. If this task is part of a tenant/domain transition or Outlook cannot connect to the intended Microsoft 365 mailbox, recreate or reconfigure the Outlook profile as appropriate.

 For troubleshooting, visit Knowledge Base articles.

 For more questions, refer to the PST to Office 365 Migration FAQs or contact the EdbMails support team.