How to fix Wired / Wi-Fi Network Device Not Managed Issue

After a recent reboot it stopped working, saying “device not managed” and you won’t be able to connect to internet. This error only happened if you’re using Network Manager to manage the network connection. For most of the time, this program works flawlessly, but it is not perfect. Now, you’re facing the problem with Device not managed issue by NetworkManager
With my exprienced, it does seem happen to Wired and Wireless Network Interfaces.

If you got this problem and this guide takes you through step by step procedures on fixing “Wired / Wi-Fi Network interface Device not managed error” in almost Linux distros from Ubuntu, Debian, Fedora, Arch Linux, Kali Linux and more …

By default, if an interface is listed in /etc/network/interfaces, NetworkManager will be smart enough and not touch these interfaces. Unmanaged devices means Network Manager doesn’t handle those network devices. And you will see this message when click on the Network Manage Applet Icon on the System Panel Thats like:

How to fix Wired / Wi-Fi Network Device Not Managed Issue
How to fix Wired / Wi-Fi Network Device Not Managed Issue

The first step, we’re looking for your network device information. To find your network device’s name, open Terminal then type:

$ ifconfig -a
enp2s0: flags=4099  mtu 1500
        ether 40:16:7e:9d:7e:ec  txqueuelen 1000  (Ethernet)
        RX packets 26215  bytes 6761702 (6.4 MiB)
        RX errors 1  dropped 954  overruns 0  frame 0
        TX packets 2401  bytes 407949 (398.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 18  

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 1  (Local Loopback)
        RX packets 15035  bytes 37818600 (36.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 15035  bytes 37818600 (36.0 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlp3s0b1: flags=4163  mtu 1500
        inet 192.168.12.1  netmask 255.255.255.0  broadcast 192.168.12.255
        inet6 fe80::1e4b:d6ff:fe3d:4cf1  prefixlen 64  scopeid 0x20
        ether 1c:4b:d6:3d:4c:f1  txqueuelen 1000  (Ethernet)
        RX packets 67988  bytes 13337456 (12.7 MiB)
        RX errors 0  dropped 46  overruns 0  frame 0
        TX packets 75909  bytes 78802387 (75.1 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

The next step, we’re check the /etc/network/interfaces file content:

[main]
plugins=keyfile
dhcp=internal
dns=default

## HTTP-based connectivity check
#[connectivity]
#uri=http://nmcheck.gnome.org/check_network_status.txt
#interval=100


[keyfile]
unmanaged-devices=interface-name:wlp3s0b1

As you see, my wireless card has been listed in unmanaged-devices section. That’s why the NetworkManager applet icon on the system tray told me that it was “device not managed”.

How to fix Wired / Wi-Fi Network Device Not Managed Issue

The solution is very simple, just comment that line or delete it from /etc/network/interfaces then restart NetworkManager service to re-enable and see it back.

On Ubuntu / Debian derivatives, you can restart NetworkManager service with the command below:

$ service network-manager restart

On Arch Linux or the Linux distro that’s using systemd to manage its services:

$ sudo systemctl restart NetworkManager

Depended on your Linux distro, you may find these string in /etc/network/interfaces instead your device’s name.

[ifupdown]
managed=false

You will need to change the bit where you see 

managed=false

to 

managed=true

Notes: Double check the /etc/network/interfaces file before save it

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