As we continue developing PVS-Studio static code analyzer, we often have to check large open-source projects by renowned developers. The fact that even such projects contain a certain amount of bugs adds even more sense and weight to our work. Unfortunately, everybody makes mistakes. No matter how carefully you control your code’s quality, there is just no way to avoid “human error”. As long as software is developed by humans, analysis tools like PVS-Studio will remain relevant and needed. Today, we are going to discuss errors found in the source code of MSBuild, which is, unfortunately, not perfect either.