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 email messages.

Solution:

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 two ways: via PowerShell or in the classic Exchange admin center.

Important

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

Use the links below to find out how to:

Note that 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 Server and Exchange Online, 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 logged 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 classic Exchange admin center

Important

Currently, in the case of Exchange Online (Microsoft 365 & Office 365), the procedure described below can be completed using the classic Exchange admin center (EAC) only. If you’re using the new Exchange admin center, you need to switch to the classic EAC by clicking Classic Exchange admin center at the bottom of the navigation menu on the left.

  1. Log in to your Exchange admin center.
  2. Go to permissions > Outlook Web App policies (see Fig. 1.; the interface is similar for all current Exchange versions).

    535-1
    Fig. 1. OWA policy in Exchange Admin Center of Office 365.

  3. Double-click the policy that is assigned to the users for whom you want to block custom OWA signatures.

    Tip

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

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

    535-2
    Fig. 2. The Email signature option (highlighted) needs be cleared/disabled.

  6. Click Save to apply the changes.

See also:

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