When organizations move to Microsoft 365, old Outlook PST archives often become one of the most important parts of the migration. These files can contain years of emails, attachments, contacts, calendars, tasks, and custom folders. The challenge is not only transferring the data but also ensuring the correct PST reaches the right mailbox while maintaining a familiar folder structure.

Microsoft provides an Azure Network Upload method for administrators who want to import PST to Office 365. The process involves assigning the required permissions, creating an import job, uploading PST files to Azure storage with AzCopy, preparing a CSV mapping file, and validating the import before starting the process. This can be useful for controlled migrations, but administrators handling a large number of PST files need to pay close attention to file mapping and job management.

For larger projects, reviewing PST contents before migration can save considerable effort. Administrators can identify which files belong to each user, check the available folders, and decide whether the complete archive or only selected data needs to be transferred. Previewing the data and applying filters can also help avoid moving unnecessary information into the destination mailbox.

The DRS Softech PST File Converter offers a dedicated workflow for handling Outlook PST data. Based on its product information, users can select individual PST files, folders, or multiple files, preview mailbox contents, and apply options such as date filtering, duplicate removal, and attachment management. These capabilities can be useful when working with historical archives that contain overlapping or unnecessary data.

Another important point is post-migration verification. After completing the PST to Office 365 migration, administrators should check a sample of destination mailboxes and verify recent emails, folders, attachments, and other migrated information. This simple validation step can help identify mapping or processing issues before the migration project is considered complete.