I've been scouring the internet and so far have only been able to find examples of how to grant calendar permissions from one user to another using the Add-MailboxFolderPermission command. This is great and it was okay for when they only had a handful of users. But going forward it's not realistic to have to set individual calendar permissions for all calendars for each new user. Layout of security groups already created. Each group has a few people assigned to it. Techs Managers Admin What I am trying to accomplish is set it up so that anyone that belongs to the Managers group can view the calendars of the Tech group. Admins can view and edit the Tech group. I've found an example of adding just the security group name but I get an error of: [PS] C:\Windows\system32add-MailboxFolderPermission -Identity Techs:\Calendar -User "Admin" -AccessRights Owner The user "Admin" is either not valid SMTP address, or there is no matching information. + CategoryInfo : NotSpecified: (0:Int32) [Add-MailboxFolderPermission], InvalidExternalUserIdException + FullyQualifiedErrorId : 39352699,Microsoft.Exchange.Management.StoreTasks.AddMailboxFolderPermission Am I creating groups wrong? Am I using the wrong commands? Any guidance would be greatly appreciated.