apt-get update

Sometime, you will get GPG error when running apt-get update after adding some unofficial supported list to your Ubuntu list.

W: GPG error: http://ppa.launchpad.net intrepid Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 28A8205077558DD0

After researching around, found a fix for this kind of situation.

Type in,

gpg –keyserver keyserver.ubuntu.com –recv 247D1CFF

However, you need to replace 247D1CFF with your NO_PUBKEY-key last eight digits from the error-message to import the key. In my case, I replace 247D1CFF with 77558DD0.

After that, add the key to the software source with below command,

gpg –export –armor 247D1CFF | sudo apt-key add -

Again, replace 247D1CFF with your NO_PUBKEY-key last eight digits from the error-message.

You should see some OK message for this 2 command. Then, try running apt-get update and it will be fine.