This one drove me bananas.

I will concede that I may have missed a line somewhere but I don’t think I did.   There are several excellent and free documents on Migrating Public Folders to Office 365 such as the one from Microsoft or this excellent reference from

However no matter what I did I ended up with an error like this EACH and EVERY time!

Error at row 1: ‘\’,’Mailbox1′. The root folder must be mapped to the primary hierarchy mailbox:PublicFolderMailbox.

Where “PublicFolderMailbox” was the actual name I assigned to the Public Folder Mailbox in Office 365.

I checked high and low and nobody could give me a “why”

Well the “Why” was pretty obvious after I looked at.  Here was my .CSV file generated from the Migration


Turns out the “Mailbox1” should be the name of your target “Public Folder” mailbox which in my case I named (Look up there ^^^ “PublicFolderMailbox”)

Changing the file to read like this


And now the rest goes easy 🙂

The Energized Tech