I'm using Concurrent Futures to run some work in parallel (futures.ProcessPoolExecutor) on windows 7 x64. The code works fine in 3.6.3, and 3.5.x before that.
I've just upgraded to 3.7.2 and it's giving me these errors:

Process SpawnProcess-6:
Traceback (most recent call last):
  File "c:\_libs\Python37\lib\multiprocessing\process.py", line 297, in _bootstrap
    self.run()
  File "c:\_libs\Python37\lib\multiprocessing\process.py", line 99, in run
    self._target(*self._args, **self._kwargs)
  File "c:\_libs\Python37\lib\concurrent\futures\process.py", line 226, in _process_worker
    call_item = call_queue.get(block=True)
  File "c:\_libs\Python37\lib\multiprocessing\queues.py", line 93, in get
    with self._rlock:
  File "c:\_libs\Python37\lib\multiprocessing\synchronize.py", line 95, in __enter__
    return self._semlock.__enter__()
PermissionError: [WinError 5] Access is denied

If I switch back to the 3.6.3 venv it works fine again.