I did some experiments with my VirtualBox VM and ran into the same problem you had with the VirtualBox guest completely locking up when I attempted an upload. I investigated the problem by checking the VirtualBox logs for the VM and found this key line that occurred at the time of the freeze:
00:03:23.540627 OHCI: Software reset
That lead me to this forum discussion:
https://forums.virtualbox.org/viewtopic.php?t=93005
where I found the solution:
https://forums.virtualbox.org/viewtopic.php?p=448185#p448185
what worked for me in this situation was to set the USB controller to USB 3.0 vs. 2.0
I'll provide more detailed instructions for that fix:
- If the VM is running, power it off (or kill it in Windows Task Manager if it is frozen).
- Switch to the VirtualBox Manager window.
- Right click on the machine that is having the freezing problem.
A context menu will open. - Select "Settings..." from the menu.
The "Settings" dialog will open. - Select "USB" from the navigation pane at the left side of the dialog.
- Select the "USB 3.0 (xHCI) Controller" radio button.
- Click the "OK" button at the bottom of the "Settings" dialog.
Now start the VM and try uploading again. This time the problem of the guest freezing should not occur.