[Solved] Unable to change processor settings on Kali Linux guest

[robertdawson]

I've installed a Kali Linux VM via VirtualBox on my Mac OS 10.11.6.

When I look at the Processor settings I see that two CPUs are attributed
to my VM. Since I've only got 4 CPUs in all, an online tutorial advises me
to reduce this to 1 CPU.
Unfortunately, the GUI in Processor settings seems unresponsive and frozen :
I cannot move the grid or edit the "2" to "1".

explain2.png (50.47 KiB) Viewed 2606 times

How can I fix this ?

[rpmurray]

Shut down the VM before trying to make the change.

[robertdawson]

Shut down the VM before trying to make the change.

Indeed. Works now, thanx for charitably answering my stupid question