Troubleshooting

Visual C++ Build Tools for C++ dependencies

Use Chocolatey (opens in a new tab) which has a package for Visual C++ Build Tools.

choco install visualcpp-build-tools

will install the latest 2017 version, but you can select one of the older versions, which include the 2015 release.

After the installation Visual Studio 2017 folder is added to the Programs menu. It includes shortcuts to various developer command prompts with cl.exe and other tools in the path.

Run the following command on a terminal with administrator permissions:

cmd /K "C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Auxiliary\Build\vcvarsall.bat" amd64

**********************************************************************
** Visual Studio 2017 Developer Command Prompt v15.0
** Copyright (c) 2017 Microsoft Corporation
**********************************************************************
[vcvarsall.bat] Environment initialized for: 'x64'

In the same session reinstall deps with:

mix deps.clean
mix deps.get
mix deps.compile