Some key things you should have in mind, when you’re moving your Exchange Organization from On Premises to Office 365, and Public Folders are in scope:
- Before moving the Public Folders to Exchange Online, you need to move all of your users (at least you should move all of the ones that require Public Folder access). Users in Exchange On Premises cannot access Public Folders in Exchange Online.
- You need to follow the Microsoft Official guidance to configure legacy on premises Public Folders under a hybrid deployment.
- You can (and should in some scenarios) point some mailboxes to the online Public Folders and that’s what this blog post is all about
Now lets look at how a Hybrid Public Folder Organization Config looks like:
As you can see above, the Public Folders in 365 are configured as remote (step 5 in the guide mentioned above), and an on premises public folder mailbox is defined as their mailbox (created in step 2 of the guide).
What this does is very simple: at the mailbox level, for each mailbox, it will set the parameter “EffectivePublicFolderMailbox” to the mailbox “OnPremPFMBX”, which is a synced mailbox object from on premises, as you can see below:
And how do we change this, per user?
The answer is simple, you run a set-mailbox cmdlet, to one or multiple users, and you define the -defaultpublicfoldermailbox parameter, to a 365 Public Folder mailbox, that you of course need to have created before hand.
set-mailbox <Mailbox> -DefaultPublicFolderMailbox 365PFMBX
The command above is what you need to run, and you can adapt if to multiple users. Let me know if you need help with that.
Before closing this blog post lets just discuss one last thing: creating the Office 365 Public Folder mailbox.
A Public folder mailbox created under a Hybrid scenario, where public folder access is set to remote, will be set by default to a HoldForMigration state. Follow this excellent BitTitan article to understand why and resolve that issue. You need to resolve it before you can create new public folders in Exchange Online.
And while doing that don’t forget that, the best tool out there to migrate your Public Folders is the BitTitan MigrationWiz tool, so while you’re in our help center go ahead and read our migration guides and ask for a quote from our sales team.