.NET: Microsoft Technologies based on the .NET software framework. Runtime: An environment required to run apps that aren't compiled to machine language.
The issue indicates a broken or incomplete .NET runtime/host installation where the cached MSI path is empty. The most reliable fix is to repair or reinstall the affected .NET runtime/host so Windows Installer no longer looks for that missing MSI.
Use these steps on Windows:
- Check installed .NET runtimes and SDKs
Open a command prompt and run:
This shows which runtimes/hosts are installed and their paths. If the host version referenced by the popup is missing or inconsistent, proceed with reinstall.dotnet --info - Repair or reinstall .NET 8 host/runtime
Since the popup mentionsdotnet-host-8.0.27-win-x64.msi, download and reinstall the matching .NET 8 runtime/host:- Go to the .NET downloads page.
- Select the .NET 8 version that matches the host version in the error.
- Under .NET Runtime, download the Installer for x64.
- Run the installer and choose Repair if offered; otherwise complete the install.
- Ensure the correct runtime/framework is present
If applications fail to launch with messages like “You must install or update .NET to run this application” or “Required framework not found”, install the specific runtime/framework indicated in the error:- From the same .NET downloads page, choose the runtime that contains the required framework (for example, .NET Runtime, ASP.NET Core Runtime, or .NET Desktop Runtime), matching the architecture (x64).
- Verify environment and paths
Ifdotnetcommands fail or the wrong architecture is resolved:- Run:
where.exe dotnet - In System Properties → Environment Variables, ensure
C:\Program Files\dotnet\appears beforeC:\Program Files (x86)\dotnet\in the systemPathso the x64 host is used first.
- Run:
- If .NET is installed in a non-default location
If a private or non-standard installation is used (for example viadotnet-installscript), setDOTNET_ROOTto that folder so apphosts and the host can find the correct installation.
After reinstalling/repairing the appropriate .NET 8 host/runtime and fixing Path/DOTNET_ROOT if needed, the installer should stop looking for the missing dotnet-host-8.0.27-win-x64.msi in the empty cache folder, and the popup should no longer appear.
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