NetworkManager refuses to manage my WLAN interface

I'm using Ubuntu 12.10 with Gnome 3.6 on a brand-new Samsung NP900X4C.

The installer detected the wireless adapter, took in the SSID and WPA passphrase, wrote these into /etc/network/interfaces and connected perfectly.

Once installation was finished I wanted to switch to using NetworkManager to manage the wireless adapter, since this is much more convenient than fiddling with /etc/network/interfaces every time I find a new hotspot.

Therefore I edited /etc/NetworkManager/NetworkManager.conf to set:

[ifupdown]
managed=true

When I rebooted NetworkManager, the problems started: - The NetworkManager tray applet changed from saying device not managed to device not ready - I lost all internet connectivity as wlan0 would not associate to the Access Point - if I set managed=false in NetworkManager.conf and restarted both NetworkManager and networking services from the command-line, the Gnome desktop "semi-crashed" and lost all its Window Decorations, the panel, the launcher and basically became unusable.

However if I restart the computer completely after setting managed=false, wlan0 once again works perfectly.

Solution 1:

I ended up fixing this myself, see the exact steps below.

Note that there may be an easier solution but these steps definitely worked.

1. Make sure network-manager is the latest version (I have 0.9.6.0-0ubuntu7 ). You can check this with: sudo dpkg -l | grep network-manager

2. Right-click on Network Manager tray icon -> Edit Connections -> Wireless -> Add Manually add the parameters for connecting to your WLAN.

3. Edit /etc/NetworkManager/NetworkManager.conf to set... [ifupdown] managed=true

   DO NOT restart network-manager service.

4. Edit /etc/network/interfaces to deactivate the auto-start of your Wireless interface (probably called wlan0).
   For example:

   From this: auto wlan0 .... to this: #auto wlan0

5. Run /etc/init.d/network-manager force-reload

Solution 2:

Uninstall wicd if you intalled it along with network-manager

If both are installed at a time, then there will be a conflict and only one will be able to use the device at a time.