Apply or remove mailbox policies for Outlook on the web and the new Outlook for Windows in Exchange Online

Article
08/29/2024

The Outlook on the web mailbox policy (formerly known as an Outlook Web App mailbox policy) that's assigned to a mailbox controls the Outlook on the web and new Outlook for Windows experience for the user. You use the Exchange admin center (EAC) or Exchange Online PowerShell to apply Outlook on the web mailbox policies to one or more mailboxes or to remove the policy assignments from mailboxes.

What do you need to know before you begin?

Estimated time to complete each procedure: 5 minutes.
You need to be assigned permissions before you can perform this procedure or procedures. For information on the permissions you need, see the "Outlook on the web mailbox policies" entry in the Feature permissions in Exchange Online article.
For information about how to open the EAC, see Exchange admin center in Exchange Online. For information about how to connect to Exchange Online PowerShell, see Connect to Exchange Online PowerShell.
For information about keyboard shortcuts that may apply to the procedures in this article, see Keyboard shortcuts for the Exchange admin center.

Apply mailbox policies for Outlook on the web and the new Outlook for Windows mailboxes

Use the EAC to apply an Outlook on the web mailbox policy to a mailbox

In the EAC, go to Recipients > Mailboxes. Or, use Outlook web app policies.
On the Manage mailboxes page, perform one of the following steps:
- Select an individual mailbox by clicking anywhere in the row other than the button option that appears in the blank area next to the Display name column.
  1. In the Details flyout that opens, select Manage email apps settings under Email apps & mobile devices section.
  2. In the Manage settings for email apps flyout that opens, delete the existing value OwaMailboxPolicy-Default from the Outlook web app mailbox policy box.
  3. In the Outlook web app mailbox policy box, start typing the name of the policy, and then select it from the results.
  4. When you're finished in the Manage settings for email apps flyout, select Save.
- Select multiple mailboxes by selecting the button option that appears in the blank area next to the Display name column in each row.
  1. Select the Edit action that appears, and then select App settings from the drop-down list.
  2. In the Manage email apps settings flyout that opens, if the Outlook web app mailbox policy box isn't visible, select Enable for Outlook on the web.
  3. In the Outlook Web App mailbox policy box, start typing the name of the policy, and then select it from the results.
  4. When you're finished in the Manage settings for email apps flyout, select Save.

Use Exchange Online PowerShell to apply an Outlook on the web mailbox policy to a mailbox

There are three basic methods that you can use to apply an Outlook on the web mailbox policy to a mailbox:

Individual mailboxes: Use the following syntax:
```
Set-CasMailbox -Identity <MailboxIdentity> -OwaMailboxPolicy "<Policy Name>"
```
This example applies the mailbox policy named "Sales Associates" to tony@contoso.com for Outlook on the web and the new Outlook for Windows.
```
Set-CASMailbox -Identity tony@contoso.com -OwaMailboxPolicy "Sales Associates"
```
Filter mailboxes by attributes: This method requires that the mailboxes all share a unique filterable attribute. For example:
- Title, Department, or address information for user accounts as seen by the Get-User cmdlet.
- CustomAttribute1 through CustomAttribute15 for mailboxes as seen the Get-Mailbox cmdlet.
The syntax uses the following two commands (one to identify the mailboxes, and the other to apply the policy to the mailboxes):
```
$<VariableName> = <Get-User | Get-Mailbox> -ResultSize unlimited -Filter <Filter>

$<VariableName> | foreach {Set-CasMailbox -Identity $_.MicrosoftOnlineServicesID -OwaMailboxPolicy "<Policy Name>"}
```
This example assigns the policy named "Managers and Executives" to all mailboxes whose Title attribute contains "Manager" or "Executive".
```
$Mgmt = Get-User -ResultSize unlimited -Filter "(RecipientType -eq 'UserMailbox') -and (Title -like '*Manager*' -or Title -like '*Executive*')"

$Mgmt | foreach {Set-CasMailbox -Identity $_.MicrosoftOnlineServicesID -OwaMailboxPolicy "Managers and Executives"}
```
Use a list of specific mailboxes: This method requires a text file to identify the mailboxes. Values that don't contain spaces (for example, the user account) work best. The text file must contain one user account on each line like this:

akol@contoso.onmicrosoft.com
ljohnston@contoso.onmicrosoft.com
kakers@contoso.onmicrosoft.com

The syntax uses the following two commands (one to identify the user accounts, and the other to apply the policy to those users):
```
$<VariableName> = Get-Content "<text file>"

$<VariableName> | foreach {Set-CasMailbox -Identity $_ -OwaMailboxPolicy "<Policy Name>"}
```
This example assigns the policy named "Managers and Executives" to the mailboxes specified in the file C:\My Documents\Management.txt.
```
$Mgrs = Get-Content "C:\My Documents\Management.txt"

$Mgrs | foreach {Set-CasMailbox -Identity $_ -OwaMailboxPolicy "Managers and Executives"}
```

For detailed syntax and parameter information, see Set-CASMailbox.

How do you know that you've successfully applied an Outlook on the web mailbox policy to a mailbox?

To verify that you've applied a mailbox policy to a mailbox for Outlook on the web and the new Outlook for Windows, perform any of the following steps:

In the EAC, go to Recipients > Mailboxes and select the mailbox. In the Details flyout that opens, select Manage email apps settings under Email apps & mobile devices, and verify the name of the policy in the Outlook web app mailbox policy box.
In Exchange Online PowerShell, replace <MailboxIdentity> with the name, alias, email address, or account name of the mailbox, and run the following command to verify the value of the OwaMailboxPolicy property:
```
Get-CasMailbox -Identity "<MailboxIdentity>" | Format-List OwaMailboxPolicy
```
In Exchange Online PowerShell, run the following command to verify the value of the OwaMailboxPolicy property for all mailboxes:
```
Get-CasMailbox -ResultSize unlimited | Format-Table Name,OwaMailboxPolicy -Auto
```

Remove mailbox policy assignments from mailboxes for Outlook on the web or the new Outlook for Windows

Use the EAC to remove the Outlook on the web mailbox policy assignment from a mailbox

In the EAC, select Recipients > Mailboxes. Or, use Outlook web app policies.
On the Manage mailboxes page, select an individual mailbox by clicking anywhere in the row other than the button option that appears in the blank area next to the Display name column.
In the Details flyout that opens, select Manage email apps settings under Email apps & mobile devices.
In the Manage settings for email apps flyout that opens, delete the existing value OwaMailboxPolicy-Default from the Outlook web app mailbox policy box.
When you're finished in the Manage settings for email apps flyout, select Save.

Use Exchange Online PowerShell to remove the Outlook on the web mailbox policy assignment from a mailbox

To remove the Outlook on the web mailbox policy assignment from a mailbox, use the following syntax:

Set-CasMailbox -Identity "<MailboxIdentity>" -OwaMailboxPolicy $null

This example removes the mailbox policy from mailbox of the user tony@contoso.com for Outlook on the web and the new Outlook for Windows.

Set-CASMailbox -Identity tony@contoso.com -OwaMailboxPolicy $null