安装 net core 后加载 hostfxr.dll 失败

Question

Anyone has this problem i change Pc and tried to install net core framework but vs code return this info when i tried to write dontet --info

Failed to load the dll from [C:\Program 
Files\dotnet\host\fxr\2.1.0\hostfxr.dll], HRESULT: 0x80070057
The library hostfxr.dll was found, but loading it from C:\Program 
Files\dotnet\host\fxr\2.1.0\hostfxr.dll failed
- Installing .NET Core prerequisites might help resolve this problem.
 http://go.microsoft.com/fwlink/?LinkID=798306&clcid=0x409

Answer 1

Installing this update will solve the problem for Windows 7 :

https://www.microsoft.com/en-us/download/details.aspx?id=26767

Answer 2

TL;DR Since the original download is no more, here's what I found on the dell forums:

Standalone package: Microsoft Update Catalog - KB4457144

I had the exact same error message (apart from the directories) on Win7 with a newer VC++ redist already present.

The package contains the KB2533623 that we want. Details of KB4457144: September 11, 2018—KB4457144 (Monthly Rollup)

After installation and a reboot, dotnet new console goes through without an error.

Dell forum source: Microsoft Windows 7 Update KB2533623 needed to install Dell Update Package (DUP)

Answer 3

I faced the same error and I checked my Web API Program.cs class and found that: .UseIISIntegration() is missing. I added it and the problem solved.

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args).UseStartup<Startup>().UseIISIntegration();
}

Answer 4

Though it is very late but I am trying to list steps to solve this issue hope, this helps! I followed the solutions provided on this link but in my case the deployment environment was the issue. listing down the steps I followed to fix this.

1. Deploy .Net core runtime with your application if not available on target machine from https://dotnet.microsoft.com/download/dotnet-core/3.1
2. set the environment variable DOTNET_ROOT
3. the appropriate deployment path/environment SIT/UAT (in my case) to solve this (a)"Deployment Mode: Self Contained" needs to be selected in Visual studio 2019. while publishing OR (b) dotnet publish -c Release -r --self-contained true
4. in case the target machine is 64 bit or 86. C:\\Program Files\\dotnet OR C:\\Program Files (x86)\\dotnet you can find the respective folder.

Answer 5

In my case there was windows7 x64 and according to this instruction: https://docs.microsoft.com/en-us/dotnet/core/install/windows?tabs=net50

Windows 7 SP1 ESU - Microsoft Visual C++ 2015-2019 Redistributable 64-bit / 32-bit

• KB3063858 64-bit / 32-bit
• Microsoft Root Certificate Authority 2011 (.NET Core 2.1 offline installer only)

There was no KB3063858 on my machine. After installation my application has started.

(I uset asp net 5)

Answer 6

I had the same problem, but in my case it was because I needed to clear my publish folder first. Apparently when you first publish as 32 bit and then as 64 bit, some files remain. When publishing to a clean folder, the error disappeared

Answer 7

This answer fixed my issue; I had built 32 bit first, then tried 64 (which was the correct build). After I deleted the publish folder and re-publishing, the hostfxr.dll problem stopped.