UPDATE: It seems that as of 16.04.1 this is not an issue for me any more.

There have been plenty of reports regarding WiFi issues on Ubuntu 16.04. The majority of issues seems to stem from suspend/resume issues where the network would not re-connect, show the wrong icon in the top bar or similar.

The temporary workaround for this is to restart the network manager if you have no network at all, or, if you have network but the nm applet is showing the wrong status, just restart the nm applet.

Restart network manager.

sudo service network-manager restart

Restart nm applet

sudo service network-manager restart

How to fix it

So, this might or it might not work for you dep. on what issue you’ve been experiencing. But this did solve it for me on two different laptops.

Lets start with figuring out what WiFi chip we have.

sudo lshw -class network

The result should look something like this:

snews@TuxBook:~$ sudo lshw -class network
       description: Wireless interface
       product: Wireless 7265
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: wlp2s0
       version: 59
       serial: 60:57:18:78:f9:92
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=4.4.0-28-generic firmware=16.242414.0 ip= latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
       resources: irq:49 memory:f7000000-f7001fff
With the above information available to us we can go to work and try to solve the resume from suspend issue.

sudo vi /etc/pm/config.d/config

In this file, paste the following

SUSPEND_MODULES="iwlwifi wlp2s0" 

The values for the suspend_modules dep. on the output from the lshw command. In my case I see that my driver is named iwlwifi and that the logical name for my chip is wlp2s0. Hence I add those to the suspend_modules line.

Now, issue a restart of the network manager;

sudo service network-manager restart

Now you should be able to suspend your laptop and when you resume it, WiFi should get reconnected automatically, and you should see the correct network type indicator in the nm applet.

The above might also work for you, so give it a try and see what happens.

Resources: http://askubuntu.com/questions/762198/16-04-lts-wifi-connection-issues - This details the /etc/pm/config.d/config config, but I had to modify it a little bit to make it work on my two laptops.