Exchange Set Retention Policy In Bulk For Specific Mailbox Type

We recently rolled out a new Retention Policy in my Exchange 2016 environment but I only wanted it to apply to Linked and User Mailboxes; not Shared or Resource Mailboxes.
We'll set a different policy for those. So I needed a way to apply this new Policy to a certain mailbox type. We'll get this done quickly with PowerShell!
 
Generally, when you apply a Retention Policy in bulk you would run Get-Mailbox | Set-Mailbox without any filters, and that would apply it to all Mailboxes in the organization.
 
We don't want that, so we'll use a filter to grab the Mailbox Type.
 
Fire up the Exchange Management Shell and run the following cmdlet:
 
Get-Mailbox -Filter {(RecipientTypeDetails -eq 'UserMailbox')} | Set-Mailbox –RetentionPolicy "UserMailbox Retention Policy"
 
The above cmdlet will apply your policy named "UserMailbox Retention Policy" to User Mailboxes only.
 
Since this is a Resource Forest, I also have Linked Mailboxes in my environment. So we'll need to apply the Policy to those as well:
 
Get-Mailbox -Filter {(RecipientTypeDetails -eq 'LinkedMailbox')} | Set-Mailbox –RetentionPolicy "UserMailbox Retention Policy"

This cmdlet will filter only Linked Mailboxes and apply the "UserMailbox Retention Policy"

**Note** Change "UserMailbox Retention Policy" to the name of your policy.

If you have multiple policies for different mailbox types, change the RecipientTypeDetails -eq 'mailboxtype' to one of the following:

UserMailbox

LinkedMailbox

SharedMailbox

RoomMailbox

EquipmentMailbox

For instance, setting a Room Mailbox Policy would look like so:

Get-Mailbox -Filter {(RecipientTypeDetails -eq 'RoomMailbox')} | Set-Mailbox –RetentionPolicy "RoomMailbox Retention Policy"

Now your different mailbox types will have the proper policies applied!