How can I migrate multiple Google Workspace mailboxes to Microsoft 365?

Migrating a single Google Workspace account to Microsoft 365 is relatively straightforward, but the process becomes more complicated when an organization has dozens or hundreds of users. Manually configuring each mailbox can take considerable time and also increases the possibility of mapping the wrong source account to a destination mailbox.

For larger migrations, I would first prepare a list containing the source Google Workspace users and their corresponding Microsoft 365 accounts. A migration tool with CSV-based mailbox mapping can then use this information to process multiple accounts in a structured way.

SysInfo Google Workspace to Office 365 Migration Tool supports bulk mailbox migration and CSV-based user mapping. It also provides separate migration modes for individual users and administrators, which can be useful depending on the size of the migration.

Before starting the actual transfer, administrators can preview mailbox folders and configure the required authentication method. The software supports options including OAuth 2.0, Modern Authentication, IMAP, App Password authentication, and Domain-Wide Delegation.

Another useful consideration is duplicate handling. During a large migration, some accounts may already contain data in Microsoft 365. The tool provides duplicate detection and can skip previously migrated items, while date filters can be used when only a specific period needs to be transferred.

I would also recommend running a small test migration before processing the entire organization. Verify mailbox mapping, folder structure, migrated messages, attachments, and other required items first. Once the configuration is confirmed, the same mapping can be used for the larger migration.