Every email subject line says [SPAM] in it

[Peter]

Every email I receive in Outlook has the word [SPAM] in
the subject line. It gets bothersome when I reply or
forward and that [SPAM] stays on the subject line.

How do I get rid of this?

 

[Lanwench [MVP - Exchange]]

What third party software are you running that might do this? Outlook
doesn't do it on its own. Check your add-ins?