"No network devices available" when wireless previously worked. (14.04)

Question

I'm running Ubuntu 14.04 on my laptop. The last time I used it (several weeks ago) the wireless was working fine. I turned it on today and no networks will show up, with the network menu saying "No network devices available."

I've disabled and enabled networking, and restarted the computer several times now. I've also tried pressing the key combination to turn the wireless adapter off and back on (FN+F2), but that didn't seem to do anything.

Most other posts I've seen while searching for solutions are cases of people having problems when they initially install the OS and not having drivers. It worked before for me so I know I have working drivers installed. I haven't messed with drivers or updated the system, or done anything with it at all since I last used it.

I've seen people on other posts request running iwconfig and ifconfig for more information, results of those below:

iwconfig:

no wireless extensions.

ifconfig:

Link encap:Local Loopback
inet addr:127.0.0.1  Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING  MTU:65536  Metric:1
RX packets:161 errors:0 dropped:0 overruns:0 frame:0
TX packets:161 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:11409 (11.4 KB)  TX bytes:11409 (11.4 KB)

Edit: Requested output of lspci -knn | grep Net -A2

02:00.0 Network controller [0280]: Qualcomm Atheros AR9485 Wireless Network Adapter [168c:0032] (rev 01)
        Subsystem: Dell Device [1028:0208]

Edit 2: Requested output of dpkg -l | grep linux-image

ii  linux-image-3.13.0-32-generic        3.13.0-32.57  amd64  Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-3.13.0-34-generic        3.13.0-34.60  amd64  Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-3.13.0-59-generic        3.13.0-59.98  amd64  Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-extra-3.13.0-32-generic  3.13.0-32.57  amd64  Linux kernel extra modules for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-extra-3.13.0-34-generic  3.13.0-34.60  amd64  Linux kernel extra modules for version 3.13.0 on 64 bit x86 SMP
ii  linux-image-generic                  3.13.0.34.40  amd64  Generic Linux kernel image

Solution

You do not have linux-image-extra for the running kernel 3.13.0-59. The kernel module ath9k is not installed. That is probably because the upgrade had been interrupted.

You need to connect to the internet by wire and run

sudo apt-get update
sudo apt-get dist-upgrade

If that does not install the extras, you can manually install them by

sudo apt-get install linux-image-extra-3.13.0-59-generic

but this means that some dependencies are not correct.

If you can't connect by wire, then boot with one of the previous kernels using grub menu. The wifi should work.

Then run the same commands.

Another option is to switch to 3.19 kernel by running

sudo apt-get install linux-generic-lts-vivid

Comments

[Admin]

Please edit your question and add output of lspci -knn | grep Net -A2 terminal command.

[Admin]

Added to original post.

[Admin]

Please also add output of dpkg -l | grep linux-image

[Admin]

Edit: Nevermind my original comment here if you saw it, adding to original post now.

[Admin]

Please post the whole output of the command to your question. It looks like you do not have the correct linux-image-extra. Can you connect to internet by wire?

[Admin]

Added it, was just a bit confused when I posted the other comment.

[Admin]

So that's what I suspected. See the answer.

[Pilot6]

That's weird. But you can run sudo apt-get install linux-image-extra-3.13.0-59-generic. That must be a bug with dependencies..

[Eli Silverhand]

Just to be clear, I should boot into 3.13.0-34 again and run that, correct?

[Pilot6]

Correct. Or the other command I added to the answer.

[Eli Silverhand]

Tried the answer you posted in the comments here, rebooted, and wireless is working fine on that now.Thanks so much for your help with this!

[Pilot6]

@EliSilverhand Run sudo apt-get dist-upgrade. You have an outdated kernel.

[Eli Silverhand]

Ran the dist-upgrade as well. Everything seems to still be working fine after that. Thanks again for your help.