Adobe Acrobat Reader shows ‘(unknown)’ next to the Default email application option when Microsoft Outlook is not the configured Windows email client.

This article applies to the following products:

SYMPTOM

When trying to share PDF documents with the Attach to Email option, the Adobe Acrobat Reader shows "Default email application (unknown)".

CAUSE

Adobe Acrobat Reader only recognizes Microsoft Outlook as an email client application, all other mail client applications appear as "unknown".

EFFECT

There is no effect on the operation of the Messageware ActiveSend or other email client applications.

MORE INFORMATION

Selecting "Remember my choice" will bypass this dialog and automatically select the default email application configured for Windows.

Updated: May 19, 2021