From time to time I see warning icons in the Dependencies node of the VS solution explorer, but with no explanatory text for what the warning is about.
The situations for when this has occurred vary, but the most recent case was when I installed the latest .NET Core 3.0 SDK build (3.0.100-preview4-011112) and then created a new ASP.NET Core Razor Components project with the latest VS2019 build from the Preview channel of VS2019 (16.1.0 Preview 1.0 [28805.205.d16.1]).
Repro steps:
Actual result:


1>------ Rebuild All started: Project: WebApplication8, Configuration: Debug Any CPU ------
1>C:\Program Files\dotnet\sdk\3.0.100-preview4-011112\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.RuntimeIdentifierInference.targets(151,5): message NETSDK1057: You are using a preview version of .NET Core. See: https://aka.ms/dotnet-core-preview
1>WebApplication8 -> C:\Users\daroth\Source\Repos\WebApplication8\WebApplication8\bin\Debug\netcoreapp3.0\WebApplication8.dll
1>WebApplication8 -> C:\Users\daroth\Source\Repos\WebApplication8\WebApplication8\bin\Debug\netcoreapp3.0\WebApplication8.Views.dll
========== Rebuild All: 1 succeeded, 0 failed, 0 skipped ==========
Expected result:
I hit another instance of these nondescript warning messages, this time with the analyzer node:



Repro:
In-progress CLI changes for FrameworkReference are resulting in the SDK node being shown incorrectly. In preview 5 this changed again, producing a different error state (see https://devdiv.visualstudio.com/DevDiv/_workitems/edit/857810).
We've discussed tool tips. The current way to show meaningful errors to the user is via the error list. This particular error is not caused by the user, nor is it something the user can fix. It's not clear what useful message could be given here.
Closing this in favour of tracking issue #4762.
I hit another instance of these nondescript warning messages, this time with the analyzer node
This is a separate issue. I suspect that more information about that error is available in the error list, or maybe as a child node in solution explorer. ~If you can reproduce it, could you open a new issue with enough information to repro it please?~ I now see the repro steps and will investigate.
@danroth27 @drewnoakes Does this analyzer node issue happen with .NET Standard 2.0? I'm not using .NET Core 3.x, but am also seeing a warning on my analyzer nodes. I'm wondering if my problem is related or if it requires creating a new issue.
@MisinformedDNA feel free to open a new issue with your repro, just in case it's a different bug.

I'm seeing this after migrating from .Net Core 2.2 to 3.0 for my Angular 7 app.
@ckelley7 that is being tracked by #5418.
Most helpful comment
I hit another instance of these nondescript warning messages, this time with the analyzer node:
Repro: