I just installed Elementary OS on my Lenovo Yoga.
During install everything worked as expected.
No when I reboot sometimes no networks are found.
To fix this I got to reboot various times.
How can I fix this ?
This may depend on the wifi adapter and its drivers as suggested by the other answer, or it may be a more broad ubuntu 16.04 buggy thing discussed in this askubuntu question: 16.04 LTS wifi connection issues.
The answer that seems to work for me in elementary is this: https://askubuntu.com/a/768268/47206.
What it says is:
sudo lshw -class network
RTL8723BE PCIe Wireless Network Adapter, the model of the card is
rtl8723bewith your own model number) Then run
echo "options rtl8723be fwlps=N" | sudo tee /etc/modprobe.d/rtl8723be.confand reboot.
If this doesn't work, one can, as an emergency solution, restart the network manager with
service network-manager restart. I find it easier to use the command
bash -c 'service network-manager restart' with a shortcut or launcher.