Anyone ever see Virtualbox stuck at starting 0%

[bobmct]

I'm running Mint 18.1 and have installed VBox from synaptic. I have3-4 VM's installed and all was working well. However, for the past day when I try to start any of the formerly working VMs the popup window "Starting VM just sits at 0% Forever. I must use a terminal, ps -ef and kill to clear it. I've also removed the install rebooted and reinstalled and tried installing a new VM. Same error.
Honestly I've been using Vbx for years and have never run across this.
Can anyone shed some light as to what might be causing this? And I will try on forums.virtualbox.org but as it seems local to Mint I thought I would try here.
Any thoughts/suggestions appreciated.

[Cosmo.]

At first make a backup of the folder VirtualBox VMs in your home (except if the VMs are dispensable).
Next open your file manager and make hidden files visible (ctrl-h). Now go into the folder .config and rename the folder VirtualBox to VirtualBox.bck
Note: VB Manager and all VMs must be closed.
Now open the VB Manager and create a new VM for testing.

[Pierre]

so I've not seen that 0% message,
but do sometimes have had it freeze at start,
& have had to abort that VB,
& sometimes even have had to log-out / log-in
in order to get the PC functioning again, which can be a real PiTA.