The problem is that the Arduino IDE is not compatible with OneDrive.
The simplest solution is to simply move your sketch somewhere else that is not in the OneDrive. You can change your sketchbook location via the Arduino IDE's File > Preferences > Sketchbook location.
For an explanation of the problem and some workarounds to allow you to use the Arduino IDE with OneDrive see this:
DarthVarner:
The Form has terrible search capability, can't find any related posts.
Well it's just Google, which isn't so bad. I would like to have some forum-specific search capabilities but in this case it's just a matter of having some good search skills. You need to know which keywords are important and which are harmful. For example, if you search for:
"readlink C:\Users\j_m_v\OneDrive\Documents\Arduino\Thimble\daddysfix\daddysfix.ino: The system cannot find the file specified."
then of course you're not going to get good results because it's too specific. Nobody else will have the path C:\Users\j_m_v\OneDrive\Documents\Arduino\Thimble\daddysfix\daddysfix.ino in their error messages except for you. If you search for:
"Error compiling for board Arduino/Genuino Uno"
then you're going to get thousands of irrelevant results because it's way too general, though I would also say that the "Arduino/Genuino Uno" part is too specific since it will filter out people who may have the same error when compiling for other boards. So a happy medium would be:
readlink "The system cannot find the file specified."