# How can I fix the BrokenProcessPool error in Qiskit?

I'm running a set of quantum circuits using the ibmq_qasm_simulator. However, sometimes my code works for the simulation, but sometimes it doesn't, and the system shows me the following message:

BrokenProcessPool: A process in the process pool was terminated abruptly while the future was running or pending.


I don't know why am I always getting this error. My Python version is 3.7.8, is there a way I can fix this issue? Thanks!

• @KAJ226 Thanks for the comment! I've seen that post and tried all the methods suggested. I was using the simulator:) – Zhengrong Jan 3 at 3:38
• Ah, I figured. Did you checked to see if it was a memory problem? – KAJ226 Jan 3 at 3:50
• How big of a circuit were you running? Since you are using ibmq_qasm_simulator then you do have up to 32 qubits... so maybe it is not an issue... have you figured out anything yet? I am curious about this myself. – KAJ226 Jan 4 at 16:36
• @KAJ226 My circuit has 8 qubits, but I'm doing 150 jobs for each running, and every single job has a list of 10 circuits. There's a Matplotlib command in my function, maybe that's the cause of my error, but sometimes it works, thats weird – Zhengrong Jan 4 at 23:54
• Matplotlib might be the cause actually. look at this thread: github.com/Qiskit/qiskit-ignis/issues/419 – KAJ226 Jan 5 at 0:16