made sure outlook 2013 is the default..
How did you do that? FWIW in the case of WLMail at least, it is necessary to use computerdefaults.exe to do it. Then it is not enough just to look and see that it is the Default E-mail client but actually set it and OK it. Doing
that makes it run an .msi file (which you can see a sign of as a small window flashes opened and closed.) Also, it may be necessary to be the owner, not just any administrator when doing it.
However, on my Surface 2 RT, where Outlook 2013 is the only possible real E-mail client that same dialog would give me no chance to try to reset it as the default. It's almost like you need to have two E-mail clients to be able to pick one explicitly
in order to get the above effect. So, for Outlook's case I would guess that I will have to find how to do a repair for it. Fortunately I haven't had to do that yet. ; )
FYI