Network manager is not detecting wifi networks

Yesterday, I upgraded from Ubuntu 16.10 to Ubuntu 17.04 and my wifi stopped working.

I noticed that I could still set up wifi manually on the console but the network manager applet wouldn't show any wifi spots and also not the active connection.

After spending 3 hours on the problem, I could fix it by a very simple step, namely modifying /etc/network/interfaces by removing (or commenting out using #) the following two lines:

auto wlan0
iface wlan0 inet dhcp

I hope this might be useful for others!

SOLVED

Go to

sudo nano /etc/network/interfaces

and deleted this line (Apparently, the above line is used to disable wifi network!)

iface wlan0 inet manual 

and then restart network manager using

sudo service network-manager restart

Run this command and hopefully it will reset your connection. sudo service network-manager force-reload