Unable to start the IIS Express Web server

Developer two 40 Reputation points
2024-03-26T16:25:16.29+00:00

Microsoft Visual Studio 2019 could not start the IIS Express Web server.

Module DLL C:\Program Files (x86)\IIS Express\aspnetcore.dll failed to load. The returned data is an error message.

I tried all kinds of methods, installed all kinds of tools and couldn't get it done.

Internet Information Services
Accepted answer
  1. Sam Wu-MSFT 7,036 Reputation points Microsoft Vendor
    2024-03-27T07:03:03.15+00:00

    @Developer two

    The reason for this problem may be that the folder corresponding to asp.net core module is missing under C:\Program Files (x86)\IIS Express, you can download from this link:

    ASP.NET Core Module (ANCM) for IIS.

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  1. Michael Taylor 48,281 Reputation points
    2024-03-26T17:01:51.4233333+00:00

    Please provide us the error message that is being returned as part of the data. We have no way of knowing what is wrong otherwise. If it fails to start at all then that indicates a configuration issue. If it fails only for a specific app then it indicates a problem with your app. Please also post what version of IISX you have installed. Newer versions of VS install newer versions of IISX.

    It may just be a simple matter of uninstalling IISX from Programs and Features or perhaps the VS Installer (if it lets you) and reinstalling it again.