In case of someone else like my face this problem it is interesting bug or so like in keil include path if path you just add include some space in folder name you will face this error and with no clue what just may cause that only clue is it include the second part of your folder(part after space) name in this error like this "Test NAME" Test(space)NAME It will show you some thing like this Keil strange main.c: Error: C4065E: type of input file "NAME" unknown And that’s it hope this help some one