Windows FAQ

This note serves as a collection of fixes for errors which may occur on the Windows platform.

The The system cannot find the path specified error (installing)

If during installation you get errors regarding missing files or unspecified paths, followed by a long path string, you might be limited by the MAX_PATH setting on windows. Try removing this limitation with these instructions.

The freeze_support error (multiprocessing)

       An attempt has been made to start a new process before the
       current process has finished its bootstrapping phase.

   This probably means that you are not using fork to start your
   child processes and you have forgotten to use the proper idiom
   in the main module:

       if __name__ == '__main__':

   The "freeze_support()" line can be omitted if the program
   is not going to be frozen to produce an executable.

The implementation of multiprocessing is different on Windows, which uses spawn instead of fork. So we have to wrap the code with an if-clause to protect the code from executing multiple times. Refactor your code into the following structure.

import minerl
import gym

def main()
    # do your main minerl code
    env = gym.make('MineRLTreechop-v0')

if __name__ == '__main__':