After upgrading to the Anniversary Update of Windows 10, all applications on my local IIS no longer work and return a 503 error instead. When looking inside IIS I noticed that my Application pools were stopped but after restarting them, they stopped when the first new request arrives. Inside the Windows Event Viewer I noticed the following error message: The Module DLL C:\WINDOWS\system32\inetsrv\aspnetcore.dll failed to load. The data is the error. To fix it, I had to repair the installation of Microsoft .NET Core 1.0.1 – VS 2015 Tooling Preview 2 : Go to “Programs and Features” Search for .NET Core Select Microsoft .NET Core 1.0.1 – VS 2015 Tooling Preview 2 from the list Click on Change and choose Repair