XAML Designer Window won't load for “Universal Windows” app - even in new project

Question

I seem to recall running into this before but can\'t for the life of me recall how I got around it and no depth of Googleing seems to help. Here\'s the problem:

When

Answer 1

It does have to do with upgrading to Windows 10. This is caused by your computer not being in Developer Mode. To fix this, on the start menu choose Settings, Update & Security, For Developers, Developer Mode, then accept the dialog. You are now in developer mode, and this should not be an issue.