Often times when a sender sends attachments using Microsoft Outlook, the attachments do not show up on Thunderbird but instead show up as a winmail.dat file that is unreadable.

There is an add-on/extension to resolve this issue for Thunderbird, it’s called LookOut.

To install the LookOut extension:

  1. Open Thunderbird
  2. Go to the Tools Menu and select “Add-ons” (If there is no menu bar, you could press Alt on your keyboard to make it appear)
  3. When the Add-ons Manager tab opens, go to the upper right corner search bar and type “lookout”
  4. Click “Install” then Click “Accept and Install…”
  5. Click “Restart now” or close and reopen Thunderbird

After the installation is complete and Thunderbird is restarted LookOut should automatically display attachments properly.