USB not working at all in guest
Applies to Windows OS only
After I changed computer, I had problems with passing through USB devices from Windows host to guest, which I used before without problems on old computer. The behaviour was wierd - all devices were visible from guest dropdown menu, but when I tried to connect them, nothing happened, and on second try there was an error:
Failed to attach the USB device XXXXX to the virtual machine YYYYY. USB device XXXXX with UUID zzzzzzz is busy with a previous request. Please try again later. Result Code: E_INVALIDARG (0x80070057) blah blah some debug shit
After that, devices are in BUSY or Connected state, but not working in guest. According to ticket #11251, it is 6 years old (if not older) known problem, but looks like Oracle gives a shit about it.
Regarding my research, it happens mostly on machines which have more built-in USB hubs or USB 3.0 ports. I found out that VBoxUSBMon filter driver captures devices but it won't create “VirtualBox USB” device, which is more or less like “connector” between guest and host. So devices on host reports “Captured” or “Busy”, but guest can't see them.
After three days of juggling with many VirtualBox builds I do have a solution, at least on my work computer (Windows 7 Pro 32bit on Dell Latitude E7440):
After that USB pass through functionality should work as expected. If not, try to turn off USB 3.0 support in BIOS.
Sound has distortions or it is slowed down in Linux guest
This is caused by improper snd_intel8x0 clock detection. Try this:
options snd-intel8x0 ac97_clock=48000
Then reboot virtual machine. In some cases audio then works normally.
Installing Guest Additions
Applies to Debian based distributions