I've been using the Windows 10 preview for a while now, quite successfully. And Outlook 2013 was behaving perfectly.

Today I was "upgraded" to the full release - and now links in emails no longer work. They give the good ol' message we're all familiar with: "Your organization's policies are preventing us from completing this action for you"

Now, we all know this message almost never has ANYTHING to do with organization policies, but is usually due to something having gone wrong with the default programs setup in the Registry

Anyway, I've tried all the usual fixes, changing to have Firefox as the default program, then to have Microsoft Edge - but to no avail.

There's a well-known Fixit for this problem on Windows 8 with Internet Explorer. We really need one for Windows 10 with Microsoft Edge.

Does anyone know where I can find it? - or alternatively do you have other ideas on how to solve the problem?

Yes BanJoCa this error is truly annoying.  I recently installed Outlook 2013 on Windows 10 and am presented with this same message when I try to copy a claim code that I received through Bing Rewards!  A simple fix is preferable.  My guess is that I get it because I'm using Edge after removing Internet Explorer.  Perhaps that should teach me about adopting the newer browsing technology!