Exchange Online PST File Migration — Microsoft 365 Mailbox Import
IT Partner performs Outlook .pst file migration to Microsoft 365 (Exchange Online) for organizations that need to move email, tasks, calendars, and contacts from .pst files into Exchange Online mailboxes.
What this engagement is
This service migrates Outlook .pst file content to Microsoft 365 (Exchange Online). Importing .pst files to user mailboxes can move an organization’s email, tasks, calendars, and contacts into Exchange Online. IT Partner can import .pst files in one of two ways: upload the data files over the network to temporary storage in the Microsoft cloud, or copy the .pst files to a hard drive with BitLocker encryption and physically ship the drive to Microsoft. Export and collection of .pst files can be performed either by IT Partner or the Client, upon agreement.
Success criteria
What you receive
How the work unfolds
Review project scope, stakeholders, PST inventory, mailbox targets, assumptions, risks, and overall project approach.
Validate PST files, confirm mailbox ownership, and approve the PST-to-mailbox mapping plan before import activities begin.
Verify Exchange Online mailbox availability, mailbox capacity, required permissions, licensing, and import prerequisites.
Configure Microsoft 365 Import Service settings, create import jobs, and prepare the import environment for execution.
Import a representative subset of PST files into selected mailboxes to validate import methodology and expected outcomes.
Review pilot import results with stakeholders and obtain approval to proceed with full production imports.
Import all approved PST files into their designated Exchange Online mailboxes according to the approved migration plan.
Verify that imported emails, folder structures, attachments, and historical content are present and accessible within target mailboxes.
Designated users confirm successful access to imported data and validate that historical content is searchable and usable.
Provide import reports, exception logs, validation results, and summary documentation detailing project outcomes.
Review final results, resolve outstanding issues within scope, obtain formal customer acceptance, and close the project.
Prerequisites
Who does what
IT Partner
- Hold a kickoff meeting to exchange contact information, plan key steps, and discuss the project
- Prepare .pst files for downloading in the selected manner
- Provide new Exchange Online mailboxes by creating Microsoft 365 user accounts and assigning Exchange Online user licenses
- Add and validate email domain(s) to Microsoft 365
- Start a migration batch
- Provide a report with the number of mailboxes that were successfully migrated and those that cannot be migrated, if any
- Set up incremental mailbox synchronization to receive any emails sent after the start of the main synchronization
- Resolve any migration issues and errors to ensure that all mailboxes have been successfully migrated
- Change DNS settings and control their application
- Monitor health and status of the destination Exchange Online environment to make sure the migration process is correct
Your team
- Export and collect .pst files (may be performed either by IT Partner or the Client, upon agreement)
- Provide a dedicated point of contact responsible for working with IT Partner and coordinate any outside vendor resources and schedules
- Configure all network equipment, such as load balancers, routers, firewalls, and switches
- Provide the authorization data necessary to complete the migration
- Ensure that contacts and calendars are exported to .pst files (if the export was performed by the Client)
- Perform changes to internal and external DNS, as required
- Assist with identification of high-risk users (top executives and VIP users, users with 50 GB mailboxes or larger and/or 30 GB deleted folders or larger)
- Review and approve engagement deliverables in a timely manner
What's not included
Limitations & technical notes
Frequently asked questions
What is included in IT Partner’s Exchange Online PST file migration service?
IT Partner’s Exchange Online PST file migration service imports Outlook .pst file content into Microsoft 365 Exchange Online mailboxes. The service includes a kickoff meeting, Microsoft 365 user and Exchange Online mailbox setup, license assignment, domain validation, PST preparation for the selected import method, migration batch start, issue resolution, DNS change control, Exchange Online environment monitoring, migration reporting, and a closeout report.
What types of Outlook data can be migrated from PST files to Exchange Online?
This service migrates Outlook .pst file content such as email, tasks, calendars, and contacts into Microsoft 365 Exchange Online mailboxes. Contacts and calendars must be included in the exported .pst files if the Client performs the export, because IT Partner can only import content that is present in the provided PST files.
How does IT Partner import PST files into Microsoft 365?
IT Partner can import PST files into Microsoft 365 in one of two ways: uploading the data files over the network to temporary storage in the Microsoft cloud, or copying the PST files to a BitLocker-encrypted hard drive and physically shipping the drive to Microsoft. The selected method is agreed during the engagement based on the project needs.
How long does the Exchange Online PST migration service take?
The stated duration for IT Partner’s Exchange Online PST file migration service is 1 week. The actual project plan may vary depending on the organization’s needs, PST file readiness, DNS timing, authorization availability, and any migration issues that need resolution.
What does the Client need to provide before the PST migration can begin?
The Client must provide a dedicated point of contact, required authorization data, timely review and approval of deliverables, and coordination with any outside vendors. The Client is also responsible for configuring network equipment, assisting with high-risk user identification, and performing internal and external DNS changes as required.
Who is responsible for exporting and collecting the PST files?
Export and collection of PST files can be performed either by IT Partner or by the Client, upon agreement. If the Client performs the export, the Client must ensure that contacts and calendars are exported to PST files when those items are expected to be migrated.
Does IT Partner create the Exchange Online mailboxes as part of this service?
Yes, IT Partner provides new Exchange Online mailboxes by creating Microsoft 365 user accounts and assigning Exchange Online user licenses. IT Partner also adds and validates email domains in Microsoft 365 as part of the migration engagement.
What happens during the PST migration engagement?
The engagement typically starts with a kickoff meeting, followed by account and mailbox setup, PST file preparation, data import from PST files, MX record changes to Exchange Online, and post-migration tasks. Post-migration work includes monitoring the destination Exchange Online environment, resolving migration issues and errors, providing migration reporting, and delivering a project closeout report.
Will mail flow be moved to Exchange Online during the project?
Yes, the implementation plan includes changing the MX record to Exchange Online and controlling the application of DNS settings. Emails can be sent and received using Exchange Online when the migration and required mail flow configuration are complete.
How does IT Partner handle email received after the main synchronization starts?
IT Partner sets up incremental mailbox synchronization to receive emails sent after the start of the main synchronization. This is included to help keep the migration aligned with mail flow changes during the transition to Exchange Online.
What business impact or downtime should we expect during the migration?
The service content does not specify a fixed downtime window, so downtime or user impact should be confirmed with IT Partner during planning. The engagement includes DNS change control, Exchange Online health monitoring, and migration issue resolution to help ensure the migration process is correct.
What reports are provided after the PST migration?
IT Partner provides a report showing the number of mailboxes that were successfully migrated and any mailboxes that cannot be migrated, if applicable. IT Partner also provides a project closeout report with final project status, evidence of matching acceptance criteria, outstanding issues if any, and the final budget.
What are the success criteria for the Exchange Online PST migration?
The service success criteria include users being able to access Exchange Online from desktop PCs, mobile phones, and tablets; PST content being uploaded to the appropriate Exchange Online mailboxes; necessary Transport rules being created and working; and email send and receive functioning in Exchange Online.
Does this service include Exchange Online Protection configuration?
No. Exchange Online Protection configuration is not part of PST migration work — importing .pst files does not change how your mail is filtered, and your existing protection settings stay as they are. If you need EOP reviewed or configured, that is scoped as separate work.
What is not included in IT Partner’s PST migration service?
Customer team training, desktop software settings, end user support, and more extensive documentation are not included in the standard service scope. These items may be available as additional services or for an additional fee, but they should be confirmed with IT Partner.
Does the service include configuring Outlook or other desktop software for end users?
No, desktop software settings are explicitly not included in the standard Exchange Online PST file migration service. If users need desktop configuration assistance, that should be discussed with IT Partner as a separate or additional service.
How are high-risk users handled during the migration?
The Client assists with identifying high-risk users, including top executives, VIP users, users with 50 GB mailboxes or larger, and users with deleted folders of 30 GB or larger. This matters because these users may require closer planning or monitoring during the Exchange Online migration.
What happens if some mailboxes or PST files cannot be migrated successfully?
IT Partner resolves migration issues and errors as part of the service to help ensure all mailboxes are successfully migrated. If any mailboxes cannot be migrated, the reporting deliverable identifies the number of successfully migrated mailboxes and those that cannot be migrated, if any.