Solving Processing path problem

Today I downloaded Processing 3.3.7 and when I ran processing.exe, I got the error message "Problem while trying to get the sketchbook" and nothing happened, Processing did not open.

I guess it is due to the fact that my windows documents folder is not in it's default location.

After searching the internet for half an hour, I found a solution (inspired by this and this):

1. Locate preferences.txt. On windows 7, it is in c:\Users\<userName>\AppData\Roaming\Processing\
2. Add the following line to preferences.txt: sketchbook.path.three=.
3. Save preferences.txt and run processing.