What’s the Best Tool for Migrating 1,000 Mailboxes from On-Premises Exchange to Exchange Online?

Microsoft's own tools are the way to go for your migration. Setting up an Exchange Hybrid configuration is pretty straightforward and should handle your volume well. Just ensure that your internet bandwidth is adequate, and be smart about your batch planning.

For a resource, you might want to take a look at this website for Exchange Hybrid migrations: [https://www.alitajran.com/exchange-hybrid/](https://www.alitajran.com/exchange-hybrid/). It could provide some good insights!

Are you planning to go fully cloud, or will you keep Active Directory? If you're maintaining AD, I strongly suggest using Microsoft's tools. You might want to avoid keeping an on-prem Exchange server if you're setting up a hybrid system. Check out the Microsoft documentation for managing hybrid exchanges—it’s really useful!

We perform these migrations frequently and usually rely on the native capabilities in Hybrid mode. It’s the most effective route, in my opinion. If you need assistance with this migration, our MSP can definitely help out.

In my experience, third-party tools tend to underperform compared to the migration options Microsoft provides. I recommend sticking with their built-in hybrid migration mechanisms for a seamless transition.