Hi Greg,
the way to fix this is to analyse your compiling process:
- set the compile-log to verbose to print all details available
- as a code-section: posting the compiler-log as a code-section
tutorial to adjust compiler-log
how to post content into a code-section
To check if the library has been really installed.
Install the file-search tool everything from voidtools
https://www.voidtools.com/
Do a search for the filename without ".h"
best regards Stefan