Disable Exchange ActiveSync for users in Microsoft 365

Original KB number: 2795303

Microsoft 365 admins can use one of the following methods to disable Exchange ActiveSync access for users:

Disable Exchange ActiveSync by using Exchange Online PowerShell

Follow these steps:

Connect to Exchange Online by using remote PowerShell. For more information about how to do this, see Connect to Exchange Online PowerShell.
Do one of the following:
- To disable ActiveSync connectivity for a single user, run the Set-CasMailbox command:
```
Set-CASMailbox -Identity <Mailbox ID> -ActiveSyncEnabled $False
```
- To disable ActiveSync connectivity for a group of users, use the Get-User command.
  
  For example, to disable ActiveSync for all the users in the Sales department, run the following command:
```
Get-User -RecipientTypeDetailsUserMailbox | where {$_.Department -eq "Sales"} | Set-CASMailbox -ActiveSyncEnabled $False
```
- To disable ActiveSync for all users in an organization, run the Get-Mailbox command:
```
Get-Mailbox | Set-CasMailbox -ActiveSyncEnabled $False
```

Follow these steps:

Sign in to the Exchange admin center as an Exchange admin.
In the left navigation pane, select Recipients > Mailboxes.
Select the user mailbox to open the flyout pane for the mailbox properties.
On the General tab, select Manage email apps settings.
In the Manage settings for email apps dialog, disable Mobile (Exchange ActiveSync) and then select Save.

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