Stop email with a blank subject line from sending?

[kwalityguy]

Sometimes I forget to fill in the subject line on a email. How do I prevent
this email from being sent? For example, in a Yahoo email, you get a prompt
before the email is actually sent, telling you that the subject line is
blank. You can then go back and correct it or choose to leave it blank.

 

[Lanwench [MVP - Exchange]]

Nothing native will do this - look at www.slipstick.com to see if there are
any add-ins.