Solving the error: device or resource busy

When you execute the command iwconfig to change the channel or the mode like this:

iwconfig wlan0 mode monitor

You usually get this error:

Error for wireless request "Set Mode" (8B06) :
        SET failed on device wlan0 ; Device or resource busy

Or if you are using airodump-ng:

ioctl(SIOCSIWMODE) failed: Device or resource busy
ARP linktype is set to 1 (Ethernet) - expected ARPHRD_IEEE80211,
ARPHRD_IEEE80211_FULL or ARPHRD_IEEE80211_PRISM instead. Make
sure RFMON is enabled: run 'airmon-ng start wlan0 <#>'
Sysfs injection support was not found either.

Solution 1

Make sure you didn't start airodump-ng yet or check if you are connected to any wifi.

If you have the command airmon-ng, check which open process could interfere.

sudo airmon-ng

For example, if the output shows the following processes:

Found 5 processes that could cause trouble.
If airodump-ng, aireplay-ng or airtun-ng stops working after
a short period of time, you may want to run 'airmon-ng check kill'

  PID Name
  332 avahi-daemon
  343 avahi-daemon
  392 wpa_supplicant
  408 wpa_supplicant
  539 dhcpcd

You need to review those processes

Solution 2

Stop ifplugd service

sudo service ifplugd stop
ifconfig wlan0 down;

Solution 3

ifconfig wlan0 down
iwconfig wlan0 mode monitor
ifconfig wlan0 up

Solution 4

If you need to change the channel and still having issues, try to use airmon-ng:

sudo airmon-ng start wlan0 11

Solution 5

Disable wpa-supplicant:

` bash service wpa_supplicant stop sudo systemctl mask wpa_supplicant.service sudo update-rc.d dhcpcd disable

Solution 6

Reboot your computer or replug the usb device.