When existing Kitematic (cmd-Q or via menu), the background VBox processes are not terminated:
Screenshot from Activity Monitor:

Output from the VBox uninstall script:
Warning! Found the following active VirtualBox processes:
1798 501 VBoxXPCOMIPCD
1800 501 VBoxSVC
1845 501 VBoxHeadless
1848 501 VBoxNetDHCP
Here is a quick command that kills all VBox processes - not very clean but a simple workaround:
pkill VBox
VirtualBox may still be running for other reasons, but we can probably kill VBoxHeadless for the Kitematic VM when the app shuts down.
Yeah fair point - but in the case where I dont use VBox outside Kitematic I would not want it to keep running. Maybe there is a way of checking this so processes are only removed if VBox is not running?
I see that this issue is closed, but I'm still experiencing this issue in the 0.5.10 beta.
Specifically, I first ran Kinematic a few days ago, started a few containers, then exited the program. Today I see, in Activity Monitor, the VBox processes. I only noticed because VBoxHeadless was consuming 1.7 GB of RAM. The other processes are only using a few MBs. Would someone be will to re-open this issue?

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Here is a quick command that kills all VBox processes - not very clean but a simple workaround: