Hi @EricJohannsen - welcome to the community.
“External issues” are those produced by third-party analysis tools, in this case a third-party Roslyn analyzer. The SonarScanner for .NET will push such third-party Roslyn issues to SonarCloud/SonarQube automatically.
However, as it says in the docs:
External issues have two important limitations:
- They cannot be managed within SonarCloud; for instance, there is no ability to mark them as False Positive.
- The activation of the rules that raise these issues cannot be managed within SonarCloud. External rules are not visible on the Rules page or reflected in any Quality Profile.
There are a couple of things you can do for third-party Roslyn issues in the SonarCloud UI:
- you can completely disable the import of third-party issues, or
- change the severity level at which they are reported.
See the C# section on this page for more information.
You can also configure which rules are run using a C# RuleSet file i.e. create an appropriate RuleSet file and reference it in your MSBuild projects.