I still cannot reproduce it in your system: [test@ixion-pld cpython]$ hostname ixion-pld [test@ixion-pld cpython]$ uname -a Linux ixion-pld 5.5.2-1 #1 SMP Wed Feb 5 19:26:43 CET 2020 x86_64 Common_KVM_processor PLD Linux [test@ixion-pld cpython]$ cat lel.py from multiprocessing.pool import ThreadPool class A(object): def __init__(self): self.pool = ThreadPool() def __del__(self): self.pool.close() self.pool.join() a = A() print(a) [test@ixion-pld cpython]$ time ./python lel.py <__main__.A object at 0x7f9130becd20> real 0m0.124s user 0m0.105s sys 0m0.021s