Hi i got this error while running the sudo apt-get update command on my Ubuntu machine :(


Fetched 308B in 1s (158B/s)
Reading package lists... Done
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 5A9BF3BB4E5E17B5
W: You may want to run apt-get update to correct these problems
  • This really does belong on superuser, even though you are getting stuck after adding a launchpad PPA.
    – Tim Post
    Commented Oct 31, 2009 at 11:52
  • yes. how can i solve this. ?
    – tutorboy.com
    Commented Oct 31, 2009 at 11:59
  • Wait for it to be migrated to superuser and you'll get plenty of help.
    – Tim Post
    Commented Oct 31, 2009 at 12:01
  • Given ~unutbu's answer I doubt it will help, but: did you try to run apt-get update to correct these problems?
    – Arjan
    Commented Oct 31, 2009 at 13:12

2 Answers 2


You need to download the gpg key:

gpg --keyserver keyserver.ubuntu.com --recv 4E5E17B5
gpg --export --armor 4E5E17B5 | sudo apt-key add -

See http://ubuntuforums.org/showthread.php?p=6626085#post6626085

  • ===gpg: keyserver timed out gpg: keyserver receive failed: keyserver error===== getting error :(
    – tutorboy.com
    Commented Oct 31, 2009 at 12:03
  • 1
    The keyserver might be down. You may have to wait and try again later. See also ubuntuforums.org/showthread.php?t=1221323 for sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 5A9BF3BB4E5E17B5 which should also fix the problem once the keyserver is working.
    – unutbu
    Commented Oct 31, 2009 at 12:21

In ubuntu 9.10, if repositories are added using the command add-apt-repository, the keys are automatically imported. This way, you don't get this error/warning.

You must log in to answer this question.