TL;DR: The default dotnet core project template does not include a ProjectGuid tag, so SonarQube skips those projects. Context: Stack Overflow #50479716 (accepted answer, 37 votes): dotnet core projects get skipped from SonarQube analysis with the warning "The following projects do not have a valid ProjectGuid and were not built using a valid solution (.sln) thus will be skipped from analysis".

```text
dotnet core projects skipped by SonarQube: missing ProjectGuid in .csproj
```

## Fix
1. The default dotnet core project template does not include a ProjectGuid tag, so SonarQube skips those projects.
   Expected: this specific failure stops.
2. Fix it in each .csproj by adding a ProjectGuid element containing a fresh GUID, nested inside a PropertyGroup element of the file.
   Expected: this specific failure stops.
3. Dont copy one GUID across projects; duplicates make the analysis treat them as the same project.
   Expected: this specific failure stops.
4. Rebuild, re-run the scanner, and the "no valid ProjectGuid" warning goes away.
   Expected: this specific failure stops.

## Details
Context: Stack Overflow #50479716 (accepted answer, 37 votes): dotnet core projects get skipped from SonarQube analysis with the warning "The following projects do not have a valid ProjectGuid and were not built using a valid solution (.sln) thus will be skipped from analysis". [accepted answer]: default dotnet core .csproj templates ship without a ProjectGuid element, and SonarQube requires one. Generate a new GUID per project (Visual Studio has Tools > Create GUID, PowerShell has New-Guid, mac and linux have uuidgen).

## When to use
You hit exactly this: dotnet core projects skipped by SonarQube: missing ProjectGuid in .csproj in dotnet core projects skipped by SonarQube.

## When not to use
A different error, or the same symptom in a different tool. This page only covers the failure above.

## Compatibility
dotnet core projects skipped by SonarQube.