I am trying to change the permissions on a calendar. I have just migrated mail over to a new Exchange 2010 server, and a new Active Directory Domain. I have used ADMT tool to migrate user accounts but I am having this same problem on a new account that was created in the new server and was not a migrated account. The error is; One or more users cannot be added to the folder access list. Non-Local users cannot be given rights on this server. This is when trying to add a USER account to the calendar permissions, and I saw the article and posts where this could not be done to distributions groups but that is not my issue. I actually CAN assign permissions to my security/distribution groups. I also saw some posts saying to make sure the mailbox is a user type and is not shared. In looking in EMC, it shows all mailbox types as user. I have ran the following command as well on the mailbox, Set-Mailbox -Identity username -Type Regular and it says that the mailbox type is already regular. Any help is appreciated!