Our IT team is preparing to retire an old Exchange Server 2010 environment, but several departments still depend on its public folders. These folders contain shared emails, contact lists, calendar entries, and historical information that must remain available after the migration. We want to avoid rushing the process and discovering permission issues once users have moved to the new environment.

The first step is to migrate Legacy Public Folders to Exchange Online only after reviewing the current folder hierarchy, mailbox capacity, usage, and access permissions. I would also create reports of the existing folders and their statistics so that the team has a reference for checking the results. Testing a representative set of folders before the full migration seems like a sensible precaution.

We are also comparing different approaches for handling the transfer. Microsoft's PowerShell-based method requires preparation of migration files, folder-to-mailbox mapping, batch synchronization, and final validation. This provides administrators with control over the process, although troubleshooting can take time when the source environment contains a large number of folders.

During this research, I found the SysInfo Office 365 to PST Export Tool, which lists features such as public folder selection, user mapping, date filtering, duplicate removal, and progress reports. These options may help with organizing migration tasks, but the exact workflow and compatibility should be confirmed before using it for a production environment.

For teams planning to migrate public folders to Office 365, what preparation steps have made the biggest difference? Do you recommend auditing permissions first, cleaning up unused folders, or testing a small migration batch? I would appreciate practical suggestions for reducing disruption and making post-migration verification more reliable.