When opening a xaml page in Visual Studio, by default the Design View is active. This takes a timely period to load and there are better Design view tools for xaml (i.e. Expression Blend)
Depending on the xaml, you may experience a Visual Studio crash.
If you need to modify the xaml, you will be unable to do so in Visual Studio until you ‘fix’ the issue Visual Studio is having with the xaml. This can be done behind the scenes using Notepad, however a more graceful approach is simply to change the default.
From the Menu Bar, Select Tools -> Options
Expand Text Editor, XAML and Select Miscellaneous.
Under Default View, check Always open documents in full XAML view
Click Ok (see images below)