How To Fix “W: GPG error NO_PUBKEY” In Ubuntu

Hey Guys,

In this tutorial, we are going to fix the error message shown below after running sudo apt-get update:

sudo apt-get update
W: GPG error: trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 52B709720F164EEB


This because mostly because you have added some PPAs to your system. We are going to fix this with WEBUPD8’s “Y PPA

Install Y-PPA

sudo add-apt-repository ppa:webupd8team/y-ppa-manager
sudo apt-get update
sudo apt-get install y-ppa-manager

Launch Y PPA from dash OR terminal:

Select “Advanced.”


Select “Try to import all missing GPG keys” from the window that appears as shown below:


Wait for some few minutes and you’re done.


sudo apt-get update