VBoxTray won't start manually (after killing it)

[GoSaneFr]

I have frequent problems with VBoxTray. ClipBoard stops working and VBoxTray is taking up to 100% of processor time. With VirtualBox version 5.0.x, I found out (I actually found the tip on several sites) that killing VBoxTray and restarting it was making everything work again. Dirty workaround but better than restarting the virtualbox every time.

But since I upgraded to kubuntu 16.10 (and VirtualBox 5.1.6), I can't restart VBoxTray. I double click the shortcut I made, the icon doesn't appear in the bottom right but I see it in the task manager but it dies after about one minute. I upgraded to the latest VirtualBox 5.1.8 but the problem is still there. I tried restarting the VirtualBox Guest additions service (yes it is the correct version) but still no luck.

Is there anything I can do ? Thanks for your help.