I have VS2012 Pro Update 3. I've downloaded and installed Windows Phone 8 SDK to create Windows Phone apps for the latest MS smartphone OS (WP8). However, I get the above-mentioned error when I try to create a new Windows Phone App project.
I deinstalled and reinstalled WP8 SDK as suggested on many forums and blogs, and even used the "repair installation" mode for VS2012 and WP8 SDK, but all this did not help.
How to get rid of this error?
P.S. My pc has Windows 8 Pro 64-bit and the CPU supports Hyper-V needed for this development (added this optional component to my Windows successfully). Other common Windows projects, such as WinForms and WPF apps, can be created and compiled without any problems in my dev env.
I solved my puzzle using the trial and errors method. Go to the TOOLS menu, then choose 'Extensions and Updates', then the Update section and install the latest NuGet update. Funny, yes?
My Solution: UNINSTALLED NuGet (as updates to it did not work)
I have installed visual studio 2012 update 3.
Go to the TOOLS menu, then choose 'Extensions and Updates', then the Update section and install visual studio update.
来源：https://stackoverflow.com/questions/19289594/creating-new-windows-phone-app-project-object-reference-not-set-to-an-instance