USB Filter Change -> VM Black Freeze

[jbalint]

Host: Linux Mint 19.1 - 64 bit, Cinnamon + VirtualBox 5.2.30 respectively 6.0.8 + appropriate Extension Pack + membership of vboxusers group
Guests: Windows10 Home 64-bit + Windows 7 Prof 32-bit + both with Guest Additions - both worked well until I changed a USB filter. Now only a black screen appears at startup, nothing more.

My two well-functioning virtual Windows-es (7 and 10) were crashed at the same time: I only changed one of the USB filter settings for one machine (the virtual machine was standing), but both virtual Windows-es died. Now they can only be shut down forced, and even the Linux Mint itself. Zombie processes run in the background that cannot be killed neither from a terminal.

I tried to reinstall the VirtualBox and also the VMs with its setting files (*vbox, VirtalBox.xml), I made several attempts. However exclusively the reinstalling of the Linux Mint system helped, then my VMs worked again. Unfortunately when I set one of the USB filter, I've got back the same black freeze again.

How could I repair my VMs without reinstalling the Linux?

[socratis]

+ VirtualBox 5.2.30 respectively 6.0.8 +

What does that mean? Are you in 5.2.30 or 6.0.8?

both worked well until I changed a USB filter

What if you change it back or remove it?

Now only a black screen appears at startup, nothing more.

I doubt that a USB filter will do that.

Unfortunately when I set one of the USB filter, I've got back the same black freeze again.

What's that, the "Kill the computer" USB filter? I need details... A lot more details about USB devices and filters. Post the output of the commands:

• VBoxManage -version
  VBoxManage list extpacks
  VBoxManage list usbhost
  VBoxManage list usbfilters

Finally, pick a VM that fails. We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Observe problem / Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

[jbalint]

VirtualBox 6.0.8 launch (https://ibb.co/z2WfmXG), then W10home64 cold boot --> Black screen forever..., the VM can't be stopped just killed. VirtualBox itself freezes too showing W10home64 is running (https://ibb.co/3p6Kcgd). I could not use its menu. I have to kill it as well. I zipped these 2 files:
~/VirtualBox VMs/W10home64/Logs/VBox.log
~/.config/VirtualBox/VBoxSVC.log
What VBox processes are still running after the massacre:
https://ibb.co/kHs8Prz
https://ibb.co/qr2W66C
Finally Linux can't be halted neither from a terminal (nor can't be it to send to sleep as normally...).
Many thanks. Sorry for the double upload, I could not delete one from Chrome.

[socratis]

Your log is incomplete. You should be grabbing the logs when the VM is completely shut-down.

[jbalint]

Your log is incomplete. You should be grabbing the logs when the VM is completely shut-down.

I would like, however, I am unable to shut-down the VM. Here are 2 desktop records what happens:
https://photos.app.goo.gl/1EW7WRqzsLKWH2yT7
I made several attempts two cure my Vbox-VM. I succeeded only when I reinstalled Linux. Still, I doubt the Linux itself spoils. Is there some more config data stored somewhere, which I can't clear even then when I totally reinstall the Vbox? I did clear the *.vbox and VirtalBox.xml files.

[jbalint]

Thank you for your ideas. Finally, the deletion of all the USB filters has resulted in the successful re-launch of the W10! Whether USB 2.0 or USB 3.0 is set - however without a single filter is set - but now it goes! Later I may test which filter causes trouble, but not now.
Many thanks.