Oh actually it maybe makes sense regarding the issue https://github.com/platformio/platformio-core/pull/3371 when one of the include folders contains a space. Since your project has
/home/greg/Documents/PlatformIO/Projects/Commodore 64 USB Keyboard/include as a include path with spaces, that could be the problem.
I can see that the
c_cpp_properties.json has been changed to fix a situation with spaces. Can you again open a PIO terminal and execute
pio upgrade --dev
Then restart VSCode. Then reopen the project and rebuild the intellisense. What’s the content of
compilerPath part should be changed from
"compilerPath": "\"/home/greg/.platformio/packages/toolchain-atmelavr/bin/avr-gcc\" -mmcu=atmega328p"
to something like
And a new project with space should be no problem anymore.