When I encountered this same error, I noticed MySQL Configuration file in "C:\Program Files\MySQL\MySQL Server X.Y\" has changed to my-default.ini
I solved it by
In the .ini file, their is part that reads:
# On Windows you should keep this file in the installation directory
# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
# make sure the server reads the config file use the startup option
# "--defaults-file".