Q1: Is dotnethost8011winx64msi a virus?
No, but the incorrectly named file could be. Always download the official dotnet-hosting-8.0.11-win-x64.exe from Microsoft. The term is a user-invented keyword, not an official Microsoft filename.

Q2: Can I use this for .NET 9.0?
No. The “8011” maps to .NET 8.0.11. For .NET 9, use the 9.x hosting bundle.

Q3: I see error “Installation failed with 0x80070643” after the fix. What now?
That is a .NET update (KB) conflict. Run the Microsoft .NET Repair Tool: https://dotnet.microsoft.com/en-us/download/dotnet-framework/net48-offline-installer (the tool is universal for .NET Core/.NET 5+ as well).

Q4: Why does the MSI keep asking for a restart?
Pending file operations from a previous installation. Reboot, then immediately run msiexec /i dotnet-hosting-8.0.11-win-x64.msi /norestart.

Some users report that even after following the above, the installation rolls back with code 0x80028011 (which is actually a type mismatch error in the Windows Installer service). Here are advanced fixes:

msiexec /i dotnethost-x64.msi /quiet /norestart