Does ASP.NET Core 1.0 installation give you an error message about Visual Studio 2015 Update 3 has not been properly installed? Here’s how to fix this.

Visual Studio 2015 neatly gives you a list of available product updates and extensions through the Notifications feature. For the past couple of weeks, Visual Studio 2015 with Update 3 has been offering me an update to the ASP.NET Core 1.0 tooling to Preview 2, but unfortunately, every time I try to launch the update from Visual Studio (after downloading the installer), I get the following error on two of my development machines:

Microsoft .NET Core 1.0.0 VS 2015 Tooling Preview 2
Setup Failed
One or more issues caused the setup to fail. Please fix the issues and
then retry setup. For more information see the log file.
Setup has detected that Visual Studio 2015 Update 3 may not be completely installed.
Please repair Visual Studio 2015 Update 3, then install this product again.

When I download the .NET Core setup from Visual Studio's link, I get the following file:

DotNetCore.1.0.0-VS2015Tools.Preview2.exe

Unfortunately, repairing Visual Studio's installation doesn't solve the issue, because the problem is not with Visual Studio or Update 3, but rather the preview installer.

To fix the issue, you need to get the preview version 2.0.1, which is only available from Microsoft .NET Core download page at present. Follow this link, and then download the installer for Windows.

You will get the following file:

DotNetCore.1.0.0-VS2015Tools.Preview2.0.1.exe

Notice the "Preview2.0.1.exe" version at the end. This update works as expected.

Problem solved!