What steps should I take if CMake error 2 occurs during the build phase?

First, clean the build directory using `cmake --build . --target clean`. Then, try building again with `cmake --build .`. If the error persists, examine the full output from CMake and `make` for more specific error messages. These messages often pinpoint the exact file or command causing the issue. Consider running `make` directly from the build directory to see its output without CMake's wrapper.