As suggested by @karann. I seems Microsoft have addressed this issue and fixed it Microsoft Visual Studio Update 3 RC. After updating my Visual Studio Enterprise Update 2 to Microsoft Visual Studio Update 3 RC I am having UWP templates.
In case anyone else is still stumpped. You may follow this Post on MSDN forum where I launched same issue and they provided an extensive set possible solution.
I don't know whether I am allowed to but I am still posting the probable solutions mentioned in the link.
(I am paraphrasing)
According to your description, it looks like the UWP development tools (1.3) and Windows 10 SDK (10.0.10586) maybe not installed correctly with VS 2015 update 2, please go to Control Panel—Programs and Features, select the VS 2015 with Updates item to change and Modify, see if the Tool (1.3) and Windows 10 SDK (10.0.10586) option as below is selected or not. In my side, after installed the VS 2015 Update 2, this option is auto-selected, which means the tools (1.3) is installed successfully, and I can create a new UWP project.
As Yoann said, please refer to this thread: https://social.msdn.microsoft.com/Forums/en-US/fe4f3ea0-245d-4189-988d-6759d1d726d2/uwpxaml-designer-failed-to-load-on-vs2015-pro-update-2?forum=visualstudiogeneral&prof=required and if the above tool (1.3) was not installed, please follow the solutions as following:
Magellan82: After investigation I noticed that Tools for Universal Windows App 1.3 never got installed. If you run the setup again and choose modify you will see that Tools for Universal Windows App 1.3 is not checked. If you try to install it, it will go through the installation and everything seems ok. But is it not. It never installs. After checking the installation logs I noticed that the installation actually fails with a BootStrapper error. This is often connected to corrupt .NET installations. I then tried to deactivate and activate .NET 3.5 but this didn't help. Then I tried to deactivate .NET 3.5 and ran the setup and added Tools for Universal Windows App 1.3 again. To my surprise it then ran through the installation with no errors and the designer worked.
NGame-IranDev: Only thing you guys need to check is:
Programs and features -> Microsoft VS2015 -> Select Change -> Goto Modify and check if the SDK v1.3 is surely installed. if it didn't try to install it and double check the installation file and make sure that now sdk v1.3 is installed. if it weren't install and check over and over to be success at last. If you finally get success in installation of SDK v1.3 your XAML designer problem will surely gone.
Andrec: Installed ".NET Framework 3.5 (includes .NET 2.0 and 3.0)" via "Turn Windows features on or off". Used Visual Studio installer from control panel which now is able to add the tools.
Holly Ta (MSFT): I had this same issue when I was updating yesterday. My solution: Go to Settings. Choose Update & Security then For developers; uncheck developer mode and check side load apps. Open Visual Studio, start a new project under the first Windows expander should be Universal, click it to start download and update of UWP templates. Once complete Switch the setting back to developer mode and open VS. All of the templates should be there now.
Sara Liu (MSFT CSG): n case, the UWP template is missing, please go to the project template store folder like C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\ProjectTemplates and check if the CSharp/Windows Root and CSharp/Windows folder are existing or not. if it exists, Please open an administrative CMD window and navigate to C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE and run the command: devenv /installvstemplates to install the default VS templates again.
Source : Link and Link2
