I need to eventually migrate 50+ Exchange mailboxes to Office 365 from another service provider. Are there any (free) tools for this? Of course I could save everything to a PST file and do a copy but that doesn't scale very well and I know it will cause problems with our users with 4 GB+ mailboxes.
Does MS offer any tools for this? I know about Migrationwiz which we used when moving from on-premises to the cloud, but I want that to be a last resort since it's a pay service.