Interface not showing up in airmon-ng

I'm running a virtual Kali machine on VirtualBox and want to connect my USB WiFi adapter to said VM.
Here are some details:

Host OS: Windows 8.1
Guest OS: Kali Linux 1.1.0a (amd64)
USB Adapter: TP-Link TL-WN725N

The adapter works perfectly during normal use in the VM and the iwconfig is as follows:

eth0 no wireless extensions.
wlan0 unassociated Nickname:"<WIFI@REALTEK>" Mode:Managed Frequency=2.412 GHz Access Point: Not-Associated Sensitivity:0/0 Retry:off RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality:0 Signal level:0 Noise level:0 Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0
lo no wireless extensions.

However, the device fails to show up in airmon-ng:

Interface Chipset Driver

And running airmon-ng start wlan0 returns: (killing the processes didn't do any good)

Found 3 processes that could cause trouble.
If airodump-ng, aireplay-ng or airtun-ng stops working after a short per
iod of time, you may want to kill (some of) them!
-e
PID Name
2188 dhclient
2275 NetworkManager
2809 wpa_supplicant
Interface Chipset Driver

And airodump-ng returns:

nl80211 not found

Am I doing something wrong? Or does the adapter simply not support monitor mode? Or do I need some drivers to get this working?

2 Answers

Try this:

airmon-ng 

And make note of your interface name, for example wlan0. Then type:

airmon-ng check kill 

Then start monitoring mode:

airmon-ng start wlan0 

Now run airmon-ng once again and note the new name of interface which will be something like this: wlan0mon

Now run airodump-ng with interface name as well:

airodump-ng wlan0mon

The same thing happened to me when I wasn't connected to the internet. I think that if you get connected to the internet some way and then run the command, it will work.