Error in Visual Studio 2015 When Add New WebForm

Question

When I add new WebForm to my project, I get the following error:

Could not load file or assembly 'Microsoft.VisualStudio.JSLS,Version=14.0.0.0 , Culture=neutral , PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.the system can not find the file specified.

I tried to create new website project and I tried to reinstall VS 2015 but this did not help.

Answer 1

This is a known bug with Visual Studio 2015. The officially-endorsed solution from Microsoft has been posted on MSDN:

If the “Tools for Universal Windows Apps Development” are still installed:

1. Go to Programs and Features, select Visual Studio 2105, click Change.
2. In Visual Studio setup, click Modify.
3. Deselect the feature “Tools for Universal Windows App Development”
4. Select “Tools for Universal Windows App Development” again, and click Update.

If you have already uninstalled the “Tools for Universal Windows Apps Development”:

1. Reinstall “Tools for Universal Windows App Development”

2. Or take the following steps to reinstall the JavaScript project system and language service:

   a. Download the installer for your edition of Visual Studio, e.g.,
   vs_community.exe.

   b. Open a CMD window, and run the following command: vs_community.exe /modify /installselectableitems JavaScript_Hidden
   /passive

Answer 2

A temporary solution:

Shut down Visual Studio and reinstall the following package from the DVD or ISO:

x:\packages\JavaScript_LanguageService\JavaScript_LanguageService.msi

A better solution, endorsed by Microsoft, has been posted.