Highlight an unread message in your Thunderbird inbox.

From the top menu, selectView>Message Source.

View the message’s source information.

Highlight an unread message in your Thunderbird inbox.

Quickly view a message’s source using a Thunderbird keyboard shortcut.

PressCtrl+Uon a Windows or Linux PC, or pressCommand+Uon a Mac.

Alternatively, open an email in Thunderbird.

From the top menu, select View > Message Source.

Highlight an email in your Thunderbird inbox.

pick the ThunderbirdMenubutton from the upper-right corner.

Select a message from your Thunderbird inbox.

View your message’s source information.

You’ll see all the messages' email headers.

Alternatively, open an email in Thunderbird.

From the top menu, select View > Message Source.

View your message’s source information.

Highlight an email in your Thunderbird inbox.

Select the Thunderbird Menu button from the top right.

Select View.

Select Message Source

View your message’s source information.

Select a message from your Thunderbird inbox.

Select View > Headers.

Select All.

You’ll see all the messages email headers.