Exchange 2010 some users mailboxes have a green arrow

This simply means that a mailbox move request exists for that user. If you expand "Recipient Configuration" you will see an item called "Move Request". Click on it to view all the existing move requests and their status. If they are all successful you can select all and clear them. That will make the green arrow go away.

Or if you like the EMS:

Get-moverequest

to view all the move reqests.

remove-moverequest <user alias>

to clear a specific move request.

get-moverequest | remove-moverequest 

to clear all move requests.

That means the mailbox was moved from one server to another but the move request has yet to be cleared.

Go to Move Requests and right-hand click on each user and choose Clear Mailbox move request