Visual Studio : Missing dll

So there I am - back to work in 2015 and rebuilding a MVC project which I haven't touched for a while and bang - error after error after ...

WTF - Happy New Year!

A long conversation with Mr. Google and:

Errors like:

Could not load file or assembly 'file:///C:\Program Files\Microsoft Visual Studio 12.0\Common7\IDE\Extensions\Microsoft\Web Tools\Publish\Microsoft.VisualStudio.Web.Publish.dll' or one of its dependencies. The system cannot find the file specified.

and

Could not load file or assembly 'file:///C:\Program Files\Microsoft Visual Studio 12.0\Common7\IDE\Extensions\Microsoft\Web Tools\Scaffolding\Microsoft.AspNet.Scaffolding.VSExtension.12.0.dll' or one of its dependencies. The system cannot find the file specified.

and

Could not load file or assembly 'file:///C:\Program Files\Microsoft Visual Studio 12.0\Common7\IDE\Extensions\Microsoft\Web Tools\Languages\Microsoft.VisualStudio.JavaScript.Web.Extensions.dll' or one of its dependencies. The system cannot find the file specified.

etc.

This is related to VS 2013 Update 4 with ancillary suspects the Azure SDK 2.5 and O365 API Tools.

The solution is to repair VS 2013 Update 4.

I have Windows 7 so:

Control Panel - Programs and Features - Installed Updates - Visual Studio 2013 Update 4 (KB2829760) - Repair.

Just take a looong break while it's running.

Enjoy!