This document lists known issues for **.NET Core 3.0 Preview releases** which may be encountered during usage.
## ASP.NET Core
### Preview 3
- **Updates to .razor files fail to show up in subsequent builds**: Updates to Razor Component (.razor) in Visual Studio may fail to show up in subsequent builds. To work around this issue add the following item group to the project file:
- **Updates to Razor Components in .razor files fail to show up in IntelliSense**: Updates to Razor Components defined in .razor files may fail to show up in IntelliSense in Visual Studio. To workaround this issue rebuild the project.
- **Single Page Applications with authentication enabled throws method not found exception when visiting the register or login pages**: The exception message is the one below.
`Method not found: 'Microsoft.EntityFrameworkCore.Metadata.Builders.IndexBuilder Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder``1.HasIndex(System.Linq.Expressions.Expression``1<System.Func``2<!0,System.Object>>)'.` To workaround this issue follow these steps:
* Replace the following package references with the ones below in your csproj folder:
- **Referencing a 3.0.0 Razor class library with Razor pages 404s**: Razor pages in 3.0.0 Razor class libraries can not be routed to. To workaround this issue re-target the Razor class library to any pre-3.0 netstandard.
- **Referencing a 3.0.0 MVC library does not work**: ApplicationParts, Controllers, Views, etc. are not discoverable in a referenced 3.0.0 MVC library. The only current way to workaround this issue is to re-target the MVC library to pre-3.0 netstandard.
- **Integration testing a MVC 3.0.0 app does not work**: Integration testing a MVC 3.0.0 app does not work. The only current way to workaround this issue is to re-target the MVC app to pre-3.0 netcoreapp.