+1

So far, I've found a way to get header path auto-complete working again in a C project under Xcode 13. From the menu bar, navigate to File -> Project Settings A modal appears showing Shared Project Settings and Per-User Project Settings. Under Per-User Project Settings, click the Advanced... button. For Build Location, select Legacy at the bottom Click Done and header auto-complete should work again. Note: I've tried doing the same with a C++ project but the C++ std library headers don't appear in the auto-complete list, rather the C headers do. (?) In a C project, typing #include <stdio.h> will now properly display a list of header names for autocomplete. This also appears to fix the issue with local project headers not auto-completing if found in a project subdirectory different than the current file. One caveat is that if you try to type in a library header, e.g. #include <SDL2/ (i.e. stopping at the forward slash), the headers found in the library do not appear in auto-complete. So in this example, SDL_image.h (one header found in the SDL2 library), will not automatically appear as an available header to be selected in the drop-down list. You would have to type it in manually; i.e. #include <SDL2/SDL_image.h>.