Tenant to Tenant Email Migration

Question

I'm trying to migrate emails from one tenant to another. My company manages both tenants and I have admin access to both. When I tried to do and IMAP Migration batch as a test, it failed. The message I received said: "Batch creation failed! Request validation failed with validation key."

Both tenants are on Office365 and using Exchange server. I'm trying to figure out the best ways to migrate emails from one set of Exchange mailboxes to another. So far my research has only pointed me towards solutions where migrations are being done from G-Suite to Office365.

Answer 1

IMAP does not work in such scenarios, and frankly, you should not be using it for Exchange mailboxes. You can either use the first-party solution Microsoft offers (https://learn.microsoft.com/en-us/microsoft-365/enterprise/cross-tenant-mailbox-migration?view=o365-worldwide) or a third-party tool, of which there are plenty. The former is free, but might involve some more work on your behalf, compared to a third-party tool. Those in turn are easier to use and might offer additional features on top, but they all come at a price.

We don't usually recommend specific third-party tools to avoid vendor spam, but you can easily find them online.