Migration from .NET 8 to .NET 9 gives an error when publishing

[J-Arturo-Sira]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have a Blazor PWA application that worked normally in AWS Amplify. After updating to .NET 9, the application, when deployed to AWS, gives these errors in the console, but it works normally both in debug and release from Visual Studio.

Any idea what it could be? I've been stuck with this error for quite a while and can't find a solution.

If you require more information, I'll gladly provide it.

Expected Behavior

After the update from .NET 8 to .NET 9 and working for a few days, upon updating it should have worked normally without throwing errors at startup.

Steps To Reproduce

1. Update project files from .NET 8 to .NET 9
2. Update available packages to their latest version in .NET 9
3. Generate the project's publish file
4. Manually upload to the hosting service (AWS Amplify)

Exceptions (if any)

Error in console: The service worker reaches the point of notifying that it was installed and activated, which is visible in the console before the errors from the image appear.

.NET Version

10.0.100-rc.2.25502.107

Anything else?

I have the latest versions of .NET 8, 9, and 10 installed, so dotnet --version returns .NET 10. However, the project is configured for .NET 9, and the error occurred before installing .NET 10 on my work machine.

[J-Arturo-Sira]

I generated the publication file from Visual Studio 2022 (latest version) and it worked completely normally, unlike the initial attempts with Visual Studio 2026 (latest version).

[javiercn]

@J-Arturo-Sira thanks for contacting us.

This is a bug in RC2 that has been fixed for RTM. Dupe of #64049