Running MSBuild 4.0 and 3.5 Side by Side on Legacy CruiseControl.NET CI
If your CI server started failing after projects were upgraded to Visual Studio 2010, the usual cause is that jobs still invoke MSBuild 3.5. This guide shows a legacy-compatible fix: install .NET 4.0, copy required MSBuild targets, and update ccnet.config while keeping 3.5 builds available.