Troubleshoot ASP.NET Core projects

By Rick Anderson

The following links provide troubleshooting guidance:

.NET Core SDK warnings

Both the 32 bit and 64 bit versions of the .NET Core SDK are installed

In the New Project dialog for ASP.NET Core, you may see the following warning:

Both 32 and 64 bit versions of the .NET Core SDK are installed. Only templates from the 64 bit version(s) installed at 'C:\Program Files\dotnet\sdk\' will be displayed.

A screenshot of the OneASP.NET dialog showing the warning message

This warning appears when both 32-bit (x86) and 64-bit (x64) versions of the .NET Core SDK are installed. Common reasons both versions may be installed include:

  • You originally downloaded the .NET Core SDK installer using a 32-bit machine but then copied it across and installed it on a 64-bit machine.
  • The 32-bit .NET Core SDK was installed by another application.
  • The wrong version was downloaded and installed.

Uninstall the 32-bit .NET Core SDK to prevent this warning. Uninstall from Control Panel > Programs and Features > Uninstall or change a program. If you understand why the warning occurs and its implications, you can ignore the warning.

The .NET Core SDK is installed in multiple locations

In the New Project dialog for ASP.NET Core, you may see the following warning:

The .NET Core SDK is installed in multiple locations. Only templates from the SDK(s) installed at 'C:\Program Files\dotnet\sdk\' will be displayed.

A screenshot of the OneASP.NET dialog showing the warning message

You see this message when you have at least one installation of the .NET Core SDK in a directory outside of C:\Program Files\dotnet\sdk\. Usually this happens when the .NET Core SDK has been deployed on a machine using copy/paste instead of the MSI installer.

Uninstall the 32-bit .NET Core SDK to prevent this warning. Uninstall from Control Panel > Programs and Features > Uninstall or change a program. If you understand why the warning occurs and its implications, you can ignore the warning.

No .NET Core SDKs were detected

In the New Project dialog for ASP.NET Core, you may see the following warning:

No .NET Core SDKs were detected, ensure they are included in the environment variable 'PATH'.

A screenshot of the OneASP.NET dialog showing the warning message

This warning appears when the environment variable PATH doesn't point to any .NET Core SDKs on the machine. To resolve this problem:

  • Install or verify the .NET Core SDK is installed.
  • Verify the PATH environment variable points to the location the SDK is installed. The installer normally sets the PATH.

Use of IHtmlHelper.Partial may result in app deadlocks

In ASP.NET Core 2.1 and later, calling Html.Partial results in an analyzer warning due to the potential for deadlocks. The warning message is:

Use of IHtmlHelper.Partial may result in application deadlocks. Consider using <partial> Tag Helper or IHtmlHelper.PartialAsync.

Calls to @Html.Partial should be replaced by @await Html.PartialAsync or the partial tag helper <partial name="_Partial" />.