Note, this error is not similar to others whereby the letters themselves are in red, this is where the project files have a red background. See the attached image below
I believe that this is because it's not marked as a content root
I've tried to set the code as "project root" but I cannot "mark directory as" on right click or within the menu
Open the code in CLion and do the same as ^
Deleted Pycharm and reinstalled it
Looked in the .xml
(I don't really know what I'm doing)
I've looked up other issues such as How to stop pycharm show files in project in red color? but they are largely irrelevant to me
The solution was to explicitly open the folder again and this makes the red background go away.
File->Open->${project folder}