Hi @cgy233, could you try reinstalling the VSCode C++ extension (ms-vscode.cpptools), and disable or uninstall the Anysphere extension (anysphere.cpptools). Attaching a screenshot for the one you’ll want:
The Anysphere extension depends on ClangD for LSP support, which requires a compile_commands.json rather than a c_cpp_properties.json. The VSCode extension will read the c_cpp_properties.json for LSP support.