In Outlook 2013, disabling signatures with Group Policy doesn’t work the same as in previous versions. The group policy setting disables adding/updating/deleting new and reply signatures, but leaves the toolbar button active to add an existing signature that was already in place. In this post i’ll go over how to disable signatures via group policy and how to disable the toolbar button as well.
To disable signatures via group policy, first step is to load the adm or admx templates for outlook. Once those are loaded, go to administrative templates, Microsoft Outlook 2013, Outlook Options, Mail format. Under mail format is an option titled “Do not allow signatures for e-mail messages” Enable this setting and signatures will be disabled for any users this GPO is applied to. In previous versions of outlook this was all that was needed. In Outlook 2013, this leaves the button in a new email message active so any existing signatures can still be added.
To completely disable signatures in Outlook 2013, we need to add one more setting. In the Outlook 2013 group policy settings, go to Microsoft Outlook 2013, Disable Items in User Interface, Custom and open “Disable command bar buttons and menu items”. Click enable and than click the show button. Add value 5608 to disable the command bar button for signatures and now users that have this policy applied will no longer be able to add existing signatures.
For additional command bar ID’s for Office 2013, Microsoft has an Office UI Help Files download containing excel files listing them all. This zip file can be found here
The Office 2013 ADMX files can be found here