Users cannot edit the calendar of room after the room mailboxes are migrated from Exchange 2007 to 2013. The owner, and the group assign be author cannot edit the calendar. What is the best way to restore the previous permission?

Hi Nahcyrret,

If there is any room mailbox still in exchange 2007,  you can compare the permission to the room mailbox which had been migrated to exchange 2013, check if there is any difference between two mailboxes. That may help you to find out the root cause which caused the issue.

If there is no room mailbox in exchange 2007, you can create a new one in exchange 2007, and check if there is the same issue on the new-created room mailbox; if not, compare it with the migrated room mailbox, and try to restore the permission.

Best regards,