> For the complete documentation index, see [llms.txt](https://wiki.owain.codes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.owain.codes/coding/umbraco/rosyln-error.md).

# Rosyln error

Every now and again you might see the error relating to csc.exe, this is how to fix it.

Within the Package Manager Console in Visual Studio type the following - **Remember the -r flag!**

`Update-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform -r`

![](https://4182918922-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MLIxsxy-PG49XtZX5uS%2F-MLwAE_0EXr12yCDaltK%2F-MLwAXV6zEp_NGrxWZl4%2FrosylnError.png?alt=media\&token=cb1bf2ed-8e6b-4f25-85fc-543edf70329f)