pitches.h

I have been trying to make a pitches.h library to make music based projects, without having to define frequencies for notes in every project, and the same for note durations (crotchets, quavers, etc)
I have the files saved but every time I do a #include command for them in a project, it says the files don't exist, even though I can open and view and edit them right there! I'm so confused! Any ideas?

I have the files saved

Where are they saved ?
What does your #include line look like exactly ?

The exact include line is as mentioned in the project book and on the arduino site - #include <pitches.h>
They're saved into the Arduino folder, which is where they automatically saved to. In my arduino folder, there's a pitches.h folder, and in that folder is the pitches.h file

With that style of #include the preprocessor will look in the Arduino libraries folders. I am not clear whether that is where you have saved pitches.h

I'll triple check that next time I use it. Thank you!