Knowledge Base

Disable Outlook on the web (OWA) signatures

This article applies to Exchange Server 2013, 2016, 2019, and Exchange Online (Office 365). For older versions of Exchange Server, i.e. 2007 and 2010, see this article.

Problem:

You would like to prevent users from creating individual Outlook on the web (OWA) signatures and adding them to emails.

Solution:

Info

If your organization’s emails are handled by Exchange Online, you can also use the modern CodeTwo Signatures Web Add-in for Outlook (a part of CodeTwo Email Signatures 365) to centrally disable native Outlook on the web signatures for the users you’ve deployed it for. Learn more

To prevent your users from adding their own email signatures in Outlook on the web, you need to disable the Email signature option in the Outlook web app mailbox policy assigned to these users. You can do it in three ways: via PowerShell, the modern Exchange admin center (Exchange Online) or the classic Exchange admin center (Exchange Server).

Important

For these solutions to work, you need to make sure your Exchange/Microsoft 365 plan supports Group Policy (GPO).

Use the links below to find out how to:

Note that disabling email signatures with the methods described below does not remove signatures that are already configured. You can use PowerShell to remove all OWA signatures - see our article to learn how to do so.

Disabling OWA signatures with a PowerShell cmdlet

This method is similar for both Exchange Online and Exchange Server, except for the first step (connection). To learn more about each connection procedure, click an appropriate link.

  1. Run Windows PowerShell to connect to your Exchange Server (as described here) or to Exchange Online (as described here). If you are signed in directly on your Exchange Server, you only need to launch Exchange Management Shell (no connection procedure required).
  2. Next, paste and execute the following cmdlet:
    Set-OwaMailboxPolicy -Identity "xyz" -SignaturesEnabled $false

    where xyz should be replaced with the name of the OWA mailbox policy which you want to modify.

    Info

    To quickly get information on available OWA mailbox policies regardless of your environment, use the following cmdlet:

    Get-OwaMailboxPolicy | Select Identity

Disabling OWA signatures in the modern Exchange admin center (Exchange Online)

  1. Sign in to the modern Exchange admin center.
  2. Navigate to Roles > Outlook web app policies, click the policy that is assigned to the users for whom you want to block custom OWA signatures, and click Manage features (Fig. 1.).

Accessing the OWA policy settings to disable/enable features.
Fig. 1. Accessing the OWA policy settings to disable/enable features.

  1. Expand the User experience feature list, clear the checkbox next to Email signature, and click Save changes to apply your settings (Fig. 2.).

Disabling email signatures in OWA in the modern Exchange admin center.
Fig. 2. Disabling email signatures in OWA in the modern Exchange admin center.

Disabling OWA signatures in the classic Exchange admin center (Exchange Server)

  1. Sign in to your classic Exchange admin center.
  2. Go to permissions > Outlook Web App policies and double-click the policy that is assigned to the users for whom you want to block custom OWA signatures (Fig. 3.).

    Tip

    See this Microsoft article to find out how to assign Outlook on the web mailbox policies to users (mailboxes).

Opening an OWA policy for editing in the classic Exchange admin center.
Fig. 3. Opening an OWA policy for editing in the classic Exchange admin center.

  1. In the window that pops up, navigate to features and expand the list of features by clicking the More options link at the bottom.
  2. On the list of features, find the Email signature checkbox and deselect it. Finally, click Save to apply your changes (Fig. 4.).

Disabling email signatures in OWA in the classic Exchange admin center.
Fig. 4. Disabling email signatures in OWA in the classic Exchange admin center.

See also:

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