Planning a PST-to-Microsoft 365 Migration for Multiple Users

General Discussions
1

A PST migration can look straightforward until an organization has to deal with hundreds of Outlook archives. I’ve seen situations where users have PST files stored on local computers, shared drives, and older backup locations. Before moving this information into Microsoft 365, the IT team needs to establish which files are still relevant and which mailbox should receive each archive.

Microsoft offers a Network Upload process for importing PST files. The administrator can configure the appropriate Microsoft 365 permissions, create an import job in Microsoft Purview, upload the PST data to Azure using AzCopy, and then provide a CSV file containing the mailbox mapping information. After validation, Microsoft processes the import into the selected mailboxes.

For a small project, this workflow may be perfectly practical. With a larger migration, I would first create an inventory of all PST files. Recording the file name, owner, approximate size, destination mailbox, and migration priority can make the project much easier to coordinate. It also helps identify duplicate archives before they are processed.

I’ve also been comparing dedicated migration applications and found the DRS Softech PST File Converter during that research. One feature I found interesting is the ability to preview PST contents before starting the conversion or migration. The software also supports batch processing, selective data handling, folder hierarchy preservation, and attachment management, which can be useful when different users have different migration requirements.

For example, an organization may want to move an employee’s complete archive while transferring only a specific date range from another user’s PST. Having filtering and selection options can make that type of project more flexible than treating every archive in exactly the same way.

When planning to import Outlook PST to Office 365, I would also recommend defining a verification process. After migration, the team can check important folders, attachments, message properties, and representative email counts. This is especially useful for archives containing business-critical correspondence that users may need to access later.

I don’t think there is one migration method that works perfectly for every organization. The native Microsoft workflow provides an established option for administrators, while specialized software can offer additional controls for batch processing and data selection. The final decision should be based on the number of PST files, available technical resources, migration requirements, and how much automation the IT team wants during the project.

2

Migrating several users from Outlook PST files to Microsoft 365 requires more than simply uploading files. The first step is to match each PST file with the correct Microsoft 365 mailbox and verify the data before migration.

  • Organize PST files by user and check mailbox contents.

  • Use PST to Office 365 migration software when handling multiple mailboxes.

  • Select required PST files and folders instead of moving unnecessary data.

  • Transfer emails, attachments, contacts, calendars, and folder structure.

  • With Softaken PST to Office 365 Importer, you can import PST data into Microsoft 365 and generate migration reports for verification.

  • Test a small group first, then migrate the remaining users.

This approach makes PST to Microsoft 365 migration more organized and reduces mailbox-mapping errors.

3

If you are migrating PST files for multiple users, it is perfect to planning the process before starting the actual import. Microsoft 365 offers manual options such as the Network Upload method, which can work well for organizations handling a manageable number of PST files. You’ll need to prepare the PST files, upload them, map them to the correct user mailboxes, and monitor the import process.

For larger or multiple PST file migrations, a dedicated tool can simplify the workflow. MailsDaddy PST to Office 365 Migration Tool is designed to help migrate PST files to Microsoft 365 while reducing the manual efforts. It can be useful when you need to handle bulk PST files and want a more straightforward migration process.

For a small migration, Microsoft’s native method may be sufficient; for multiple users and larger PST collections, using a dedicated migration tool can save considerable time and effort.

4

If you are planning for a PST to Microsoft 365 migration involving multiple users, the first thing to sort out is the PST to mailbox mapping. Each Outlook archive should go to the correct Microsoft 365 account, especially when different users have different folders and archive sizes.

If the migration involves several PST files, a dedicated utility can save the manual effort of importing each archive separately. In one such setup, DataVare PST to Office 365 Converter Expert came into the workflow because the PST files needed to be transferred directly to their respective Microsoft 365 mailboxes. It supports email attachments, folder hierarchy, and selective mailbox data and does not require Outlook for the migration.