Microsoft recently published the first preview for the upcoming .NET SDK 5.0. Rider does not yet provide official support for the newest SDK. Before we run the full QA cycle to identify all the situations where Rider behaves incorrectly, we’re going to wait for more stable bits of the SDK (right now .NET 5 itself has many issues to fix). We will get Rider fully tested on .NET SDK 5.0 closer to the .NET SDK 5.0 release.
If you’ve noticed any other problems which you think might be related to the installed .NET SDK 5.0-preview, please keep in mind that it might be a current limitation of .NET SDK or simply a bug in the preview. If you still think it is a Rider issue, please file a new issue on YouTrack and explicitly mention that the preview SDK is installed.
We plan to provide full support for .NET SDK 5.0 in Rider 2020.3 release later this year.