Please refer to: https://docs.python.org/3.6/library/multiprocessing.html
the first example program. If I run it on Windows 10 (Python 3.6.4) or Linux Mint 18 (Python 3.5.2), it works as expected. On Windows Server 2012, however, I get no (none!) output, no matter if I run with admin rights or not: adminnkj@DTDKCPHAS1060 ~ $ python3 -V Python 3.6.4 adminnkj@DTDKCPHAS1060 ~ $ cat test.py from multiprocessing import Pool def f(x): return x*x if __name__ == '__main__': p = Pool(5) print(p.map(f, [1, 2, 3])) adminnkj@DTDKCPHAS1060 ~ $ python3 test.py ---> NB: no output <--- adminnkj@DTDKCPHAS1060 ~ $ echo $? 0 ---> NB: Normal exit code <--- I am a bit lost, running with -v -vv or -vvv does not help me much (here are the last lines of the latter): (cut) import 'multiprocessing.connection' # <_frozen_importlib_external.SourceFileLoader object at 0xffc913f0> import 'multiprocessing.queues' # <_frozen_importlib_external.SourceFileLoader object at 0xffc7ab10> # trying /usr/lib/python3.6/multiprocessing/synchronize.cpython-36m-i386-cygwin.dll # trying /usr/lib/python3.6/multiprocessing/synchronize.abi3.dll # trying /usr/lib/python3.6/multiprocessing/synchronize.dll # trying /usr/lib/python3.6/multiprocessing/synchronize.py # /usr/lib/python3.6/multiprocessing/__pycache__/synchronize.cpython-36.pyc matches /usr/lib/python3.6/multiprocessing/synchronize.py # code object from '/usr/lib/python3.6/multiprocessing/__pycache__/synchronize.cpython-36.pyc' import 'multiprocessing.synchronize' # <_frozen_importlib_external.SourceFileLoader object at 0xffc91af0> # trying /usr/lib/python3.6/multiprocessing/popen_fork.cpython-36m-i386-cygwin.dll # trying /usr/lib/python3.6/multiprocessing/popen_fork.abi3.dll # trying /usr/lib/python3.6/multiprocessing/popen_fork.dll # trying /usr/lib/python3.6/multiprocessing/popen_fork.py # /usr/lib/python3.6/multiprocessing/__pycache__/popen_fork.cpython-36.pyc matches /usr/lib/python3.6/multiprocessing/popen_fork.py # code object from '/usr/lib/python3.6/multiprocessing/__pycache__/popen_fork.cpython-36.pyc' import 'multiprocessing.popen_fork' # <_frozen_importlib_external.SourceFileLoader object at 0xffc57190> then it exits with no further output. Best regards, Niels Kristian Jensen (from Denmark) -- https://mail.python.org/mailman/listinfo/python-list