Python Multiprocessing - PermissionError: [WinError 5] Access is denied

Question

I am using multiprocessing to run a function I have multiple times, at the same time. I get this error: PermissionError: [WinError 5] Access is denied I assumed it meant I needed to run the program as an administrator so I ran it as administrator but now it just crashes. I am running the multiprocessing like this:

p1 = multiprocessing.Process(target=exMine)
p2 = multiprocessing.Process(target=exMine)
p3 = multiprocessing.Process(target=exMine)
p4 = multiprocessing.Process(target=exMine)

if __name__ == '__main__':
   p1.start()
   p2.start()
   p3.start()
   p4.start()

I saw some other posts about this error but it had to do with the Python version (Specifically 3.7) . I get the same error running this in Python 3.8.3 and Python 3.9.1

The full error is:

Traceback (most recent call last):
  File "miner.py", line 389, in <module>
    lgdIn()
  File "miner.py", line 182, in lgdIn
    mine()
  File "miner.py", line 174, in mine
    p1.start()
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\process.py", line 121, in start
    self._popen = self._Popen(self)
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\context.py", line 326, in _Popen
    return Popen(process_obj)
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\popen_spawn_win32.py", line 93, in __init__
    reduction.dump(process_obj, to_child)
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
AttributeError: Can't pickle local object 'lgdIn.<locals>.mine.<locals>.exMine'

C:\Users\deanm\Programming\Full-on Big Projects\TimerCoin\Program>Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\spawn.py", line 107, in spawn_main
    new_handle = reduction.duplicate(pipe_handle,
  File "C:\Users\deanm\anaconda3\lib\multiprocessing\reduction.py", line 79, in duplicate
    return _winapi.DuplicateHandle(
PermissionError: [WinError 5] Access is denied

Does this answer your question? [Python multiprocessing PicklingError: Can't pickle ](https://stackoverflow.com/questions/8804830/python-multiprocessing-picklingerror-cant-pickle-type-function) — Chayim Friedman, Jan 25 '21 at 20:30
@ChayimFriedman It's the name of the function I want to run multiple times. — dean0x45, Jan 25 '21 at 20:56
@ChayimFriedman Not really, I am using the module in a different way. — dean0x45, Jan 25 '21 at 20:57
@scenox Yeah, that is pretty much the same just there isn't a resolution there. — dean0x45, Jan 25 '21 at 21:08
Just a quick suggestion but for my multiprocessing needs I use the pathos module. Not only does it have a multiprocessing pool (which seems to be what you need from the code example I see) but it also tends to not bug as much as the built-in multiprocessing module. — alex_bits, Jan 25 '21 at 21:21
I am getting the same error. I tried to switch to pathos.multiprocessing, unfortunetely the program gives errors ( it can not find Process on that package). Did you find the solution for the problem? — Ferda-Ozdemir-Sonmez, Jul 22 '21 at 20:08

Python Multiprocessing - PermissionError: [WinError 5] Access is denied

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