#FAQ Friday: 2 Fast Ways to Disable OWA in Less Than 2 Minutes!


In our world of IT support, admins often find that they want to block certain users or departments from accessing Outlook Web Application (OWA) aka Outlook on the Web. Whether it’s because there are employees or contractors who don’t need to access their mail from external computers, phones, or browsers, or other security reasons, it’s useful to know how to block users from accessing their work email via OWA without changing the configuration for all.

Here’s how it’s done.
At high level, there’s two different ways you can shut off or disable OWA with Exchange Online or Exchange 2016.
  1. Exchange Admin Center; or
  2. Exchange PowerShell

How to use the Exchange Admin Center to disable OWA.

Are there only a few users you would like to shut off OWA for? Do you only need to shut it off on a case-by-case basis? If so, we recommend using the Exchange Admin Center to disable it.

1. Go to the Exchange Admin Center (EAC). Then, click on Recipients > Mailboxes.
2. Find the mailbox you’d like to disable Outlook Web App for, and then select Edit.
3. This will bring you to the mailbox properties page/pop up window. Click Mailbox Features.
4. Find the Email Connectivity heading. Change the Outlook on the Web setting from Enabled to Disable. Click save. At the warning message, click Yes.
Alternatively, as a short-cut option, in the recipient mailbox user list, if you highlight the user mailbox, on the right-hand side, you can click on Disable under Email Connectivity – Outlook on the Web, and save the change to confirm.
And there you have it! You’ve managed to disable OWA for a mailbox!

Now it’s time to double check your work.

It’s a good practice to take a moment to make sure your changes were successfully applied. After all, there are often times when Office 365 / Exchange Online or Exchange 2016 experiences issues with saving changes (we’ve been there!).

Checking your Outlook on the Web disable changes doesn’t take much time, but can save you a headache later.

Steps to check the Outlook on the Web disable changes:

  1. Go to the Exchange Admin Center. Select Recipients, then Mailboxes.
  2. Find the mailbox you’d like to check the OWA disable setting for, and click Edit.
  3. On the Mailbox Properties page, click Mailbox Features.
  4. In the Email Connectivity field, take note of whether Outlook Web App is enabled or disabled.

Now, what if you want to disable OWA for multiple users and you'd rather use PowerShell?

Often, IT admins don’t have just one user to disable OWA for. In fact, we’ve seen customers with large environments that want to disable hundreds or thousands at a time. While the Exchange Admin Center option may be ideal for disabling a few at a time, disabling OWA for hundreds, or even thousands of accounts would be a daunting task.

Luckily, that’s where PowerShell comes in.

Use PowerShell to disable OWA:
  1. Start Exchange PowerShell.
  2. If you’re using Exchange Online, log in.
    • Connect-msolservice [enter admin credentials for O365]
    • $usercredential = Get-Credential [enter admin credentials for O365]
    • $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
    • Import-PSSession $Session
  3. Enter the following command: Set-CASMailbox -Identity "EXAMPLE USER" -OWAEnabled $false

Using PowerShell to check the OWA Enable / Disable setting:

If you want to check the OWA Enable / Disable setting for a user’s mailbox, enter the following cmdlets into Exchange PowerShell:

Enter the following command: Get-CASMailbox <identity>

If Outlook Web App is disabled, it will come back as “false”. If it is enabled, the value will display as “true”.
And that's that!