Solved by colesbury in post #2 
              
              
                Your background process needs to be alive when the main process reads the tensor. 
Here’s a small modification to your example: 
import multiprocessing as mp
import torch

done = mp.Event()

def extractor_worker(done_queue):
    done_queue.put(torch.Tensor(10,10))
    done_queue.put(None)
    done.w…