#### 1. dotnet test x64 emulation on arm64 support
While a lot of work has been done to support arm64 emulation of x64 processes in .net 6, there are some remaining [work](https://github.com/dotnet/sdk/issues/21686) to be done in 6.0.2xx. The most impactful remaining item is `dotnet test` support.
`dotnet test --arch x64` on an arm64 machine will not work as it will not find the correct test host. To test x64 components on an arm64 machine, you will have to install the x64 SDK and configure your `DOTNET_ROOT` and `PATH` to use the x64 version of dotnet.
#### 2. Upgrade of Visual Studio or .NET SDK from earlier builds can result in a bad `PATH` configuration on Windows
When upgrading Visual Studio to preview 5 or the .NET SDK to RC2 from an earlier build, the installer will uninstall the prior version of the .NET Host (dotnet.exe) and then install a new version. This results in the x64 `PATH` being removed and added back. If a customer has the x86 .NET Host installed, this one will end up ahead of the x64 one and will be picked up first.
Different architectures of .NET do not know about each other so then the .NET SDK will stop functioning correctly (behavior may be Visual Studio unable to create projects, dotnet new fails, etc).
To confirm, run `dotnet --info` and you'll see (x86) paths for all of the found .NET runtimes and .NET SDKs installed. To resolve this, remove "c:\program files (x86)\dotnet" from the `PATH` environment variable or move it after "c:\program files\dotnet"
As of .NET 6 Preview 1, there is an ongoing issue with running Blazor WebAssembly applications using an IIS Express server during development on Visual Studio. As a workaround, we recommend using Kestrel during development.
As of .NET 6 Preview 5, when using the JWT Bearer handler in a time zone that is higher than UTC (e.g. Eastern European Time/UTC+2), you may observe an `ArgumentOutOfRangeException` if the JWT token does not contain a `nbf` value (valid from).
Issue is tracked by https://github.com/dotnet/aspnetcore/issues/33634 and will be fixed in .NET 6 Preview 6.
**Workaround**
You can workaround this by always providing a non-zero and non-minimum value for the `notBefore` parameter when using System.IdentityModel.Tokens.Jwt.JwtSecurityToken, or the 'nbf' field if using another JWT library.
When enabling HTTP/3 which is only accessible through a feature flag, you might experience Kestrel using 100% of the CPU. We recommend not enabling the feature until this is fixed.
Issue is tracked by https://github.com/dotnet/runtime/issues/60133 and will be fixed in .NET 6 RTM.
There is a known issue with modifying the `WebRootPath` in a minimal app using the `WebApplicationBuilder` as documented in https://github.com/dotnet/aspnetcore/issues/36999. The issue will be resolved in .NET 6 RTM. As a workaround, users can use the default `wwwroot` directory for serving static files in their applications. Alternatively, you can invoke `UseStaticFiles` with a `StaticFilesOption` containing both the provider and path.
```csharp
app.UseStaticFiles(new StaticFileOptions
{
ContentTypeProvider = new PhysicalFileProvider("/full/path/to/custom/wwwroot")
A regression introduced in .NET 6 RC2 prevents configuration from being reloaded on changes when using `WebApplication.Create()` and `WebApplication.CreateBuilder()`. This includes both custom configuration sources and default configuration sources such as `appsettings.json`.
The first time SPA apps are run, the authority for the spa proxy might be incorrectly cached which results in the JWT bearer being rejected due to Invalid issuer. The workaround is to just restart the SPA app and the issue will be resolved. If restarting doesn't resolve the problem, another workaround is to specify the authority for your app in Program.cs: `builder.Services.Configure<JwtBearerOptions>("IdentityServerJwtBearer", o => o.Authority = "https://localhost:44416");` where 44416 is the port for the spa proxy.
When using localdb (default when creating projects in VS), the normal database apply migrations error page will not be displayed correctly due to the spa proxy. This will result in errors when going to the fetch data page. Apply the migrations via 'dotnet ef database update' to create the database.