The ValidateAddInXMLTask task failed unexpectedly

Error Message

When compiling an ArcObjects add-in using Microsoft Visual Studio 2015, the following error may be returned:

Error:   
"The ValidateAddInXMLTask task failed unexpectedly. System.IO.FileNotFoundException:
Could not load file or assembly 'Microsoft.VisualStudio.Shell.12.0, Version=12.0.0.0,
Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.
The system cannot find the file specified."

Cause

ArcGIS Desktop and Engine add-ins have a dependency on the Microsoft Visual Studio Shell 12.0 library.
This error occurs when using Visual Studio 2015 without this library.

Note:
If Visual Studio 2013 and 2015 are both installed on the machine, this problem does not occur. Older versions of Visual Studio include the Microsoft Visual Studio Shell 12.0 library.

Solution or Workaround

1. To resolve this issue, download and install the appropriate package that includes the Microsoft Visual Studio 12.0 Shell library:
   Download: Microsoft Visual Studio redistributable Packages
2. Compile the add-in again with Visual Studio 2015.