Using the Open Source code analysis tool ConQAT, I created a C# clone analysis by clicking
New->Run config->code_clones->CsCodeAnalysis.
When I run it, the report says for each C# file:
No factory found for element myproject/myfile.cs
Is it a bug in ConQAT?
I guess you were using Cs*Clone*Analysis.
This configuration reads the solution files to determine the actual C# files that are included in the analysis. From the message I would guess that you tried to directly pass the C# files in, which does not work. As the files do not end in .sln you get an error.
See the ConQAT examples (clonedetection-example-nunit.cqr) for how to use this configuration.
It is also possible to directly pass C# files to a clone detection, but you would need a different configuration then.