Nothing connected to bound method vmmVMWindow.control_vm_pause

This error appeared after upgrading to Fedora 36 and leaving Virt-Manager (Virtual Machine Manager) running for few days.

Reconnecting to my session, I couldn’t open (or start) any VM, since most clicks were followed by this popup:

I’ve tried to restart Virt-Manager, but I was encountering the same behavior.

Finally, the problem was that virt-manager was still running in the background, even if the GUI part was closed:

$ ps -ef | grep python
root      1056      1 0 Jan31 ? 00:00:00 /usr/bin/python3 -s /usr/sbin/firewalld --nofork --nopid
root      1159      1 0 Jan31 ? 00:02:12 /usr/bin/python3 /usr/bin/supervisord -c /etc/supervisord.conf
viulian 411081 410754 0 Feb07 ? 00:00:01 /usr/bin/python3 /usr/bin/blueman-applet
viulian 412909      1 0 Feb07 ? 00:58:56 /usr/bin/python3 /usr/bin/virt-manager
viulian 714827 714779 0 15:30 pts/4 00:00:00 grep --color=auto python

A kill -9 412909 fixed the problem.

The full message was:

Error launching details: nothing connected to <bound method vmmVMWindow.control_vm_pause of <vmwindow.vmmVMWindow object at 0x7f4cf897c880 (virtManager+vmwindow+vmmVMWindow at 0x55d716a88aa0)>>

Traceback (most recent call last):

File “/usr/share/virt-manager/virtManager/vmwindow.py”, line 475, in set_pause_state

src.handler_block_by_func(self.control_vm_pause)

TypeError: nothing connected to <bound method vmmVMWindow.control_vm_pause of <vmwindow.vmmVMWindow object at 0x7f4cf897c880 (virtManager+vmwindow+vmmVMWindow at 0x55d716a88aa0)>>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

File “/usr/share/virt-manager/virtManager/vmwindow.py”, line 40, in get_instance

cls._instances[key] = vmmVMWindow(vm)

File “/usr/share/virt-manager/virtManager/vmwindow.py”, line 157, in __init__

self._refresh_vm_state()

File “/usr/share/virt-manager/virtManager/vmwindow.py”, line 425, in _refresh_vm_state

self.set_pause_state(paused)

File “/usr/share/virt-manager/virtManager/vmwindow.py”, line 478, in set_pause_state

src.handler_unblock_by_func(self.control_vm_pause)

TypeError: nothing connected to <bound method vmmVMWindow.control_vm_pause of <vmwindow.vmmVMWindow object at 0x7f4cf897c880 (virtManager+vmwindow+vmmVMWindow at 0x55d716a88aa0)>>