New to Ubuntu. In the other sofware sources i have "Debian 4.0 eth" officially supported "non-us.debian.org/"; etc ... "ppa.launcpad.net" and installing applications has stopped working. I think i first came across this problem after installing Blender 2.58 When using update manager it is prompting for a partial upgrade. Almost every software when trying to install showing the same error Package Dependencies Error or GPG PUB KEY missing, tried to fixing to them but no luck. Output to: sudo apt-get update && sudo apt-get upgrade (links disabled http:// -- http:/ as new user can't put more no. of hyperlinks) Ign http:/non-us.debian.org stable/non-US InRelease Ign http:/non-us.debian.org stable/non-US Release.gpg Ign http:/non-us.debian.org stable/non-US Release Ign http:/non-us.debian.org stable/non-US/contrib TranslationIndex Ign http:/non-us.debian.org stable/non-US/main TranslationIndex Ign http:/non-us.debian.org stable/non-US/non-free TranslationIndex Err http:/non-us.debian.org stable/non-US/main Sources 503 Service Unavailable Err http:/non-us.debian.org stable/non-US/contrib Sources 503 Service Unavailable Err http:/non-us.debian.org stable/non-US/non-free Sources 503 Service Unavailable Err http:/non-us.debian.org stable/non-US/main amd64 Packages 503 Service Unavailable Err http:/non-us.debian.org stable/non-US/contrib amd64 Packages 503 Service Unavailable Err http:/non-us.debian.org stable/non-US/non-free amd64 Packages 503 Service Unavailable Ign http:/non-us.debian.org stable/non-US/contrib Translation-en_IN Ign http:/non-us.debian.org stable/non-US/contrib Translation-en Ign http:/non-us.debian.org stable/non-US/main Translation-en_IN Ign http:/non-us.debian.org stable/non-US/main Translation-en Ign http:/non-us.debian.org stable/non-US/non-free Translation-en_IN Ign http:/non-us.debian.org stable/non-US/non-free Translation-en Ign http:/archive.ubuntu.com natty InRelease Ign http:/archive.canonical.com natty InRelease Ign http:/extras.ubuntu.com natty InRelease Ign http:/http.us.debian.org stable InRelease Ign http:/ftp.us.debian.org etch InRelease Ign http:/archive.ubuntu.com natty-updates InRelease Hit http:/archive.canonical.com natty Release.gpg Get:1 http:/extras.ubuntu.com natty Release.gpg [72 B] Ign http:/ppa.launchpad.net natty InRelease Get:2 http:/http.us.debian.org stable Release.gpg [1,672 B] Ign http:/linux.dropbox.com natty InRelease Ign http:/ftp.us.debian.org etch Release.gpg Ign http:/archive.ubuntu.com natty-security InRelease Hit http:/archive.canonical.com natty Release Hit http:/extras.ubuntu.com natty Release Ign http:/ppa.launchpad.net natty InRelease Get:3 http:/linux.dropbox.com natty Release.gpg [489 B] Ign http:/ftp.us.debian.org etch Release Ign http:/dl.google.com stable InRelease Get:4 http:/archive.ubuntu.com natty Release.gpg [198 B] Ign http:/ppa.launchpad.net natty InRelease Hit http:/archive.canonical.com natty/partner Sources Hit http:/extras.ubuntu.com natty/main Sources Get:5 http:/linux.dropbox.com natty Release [2,599 B] Get:6 http:/archive.ubuntu.com natty-updates Release.gpg [198 B] Ign http:/ppa.launchpad.net natty InRelease Hit http:/archive.canonical.com natty/partner amd64 Packages Hit http:/extras.ubuntu.com natty/main amd64 Packages Get:7 http:/linux.dropbox.com natty/main amd64 Packages [784 B] Get:8 http:/archive.ubuntu.com natty-security Release.gpg [198 B] Ign http:/ppa.launchpad.net natty InRelease Ign http:/archive.canonical.com natty/partner TranslationIndex Ign http:/extras.ubuntu.com natty/main TranslationIndex Get:9 http:/http.us.debian.org stable Release [104 kB] Ign http:/linux.dropbox.com natty/main TranslationIndex Hit http:/archive.ubuntu.com natty Release Ign http:/ppa.launchpad.net natty InRelease Ign http:/http.us.debian.org stable Release Hit http:/archive.ubuntu.com natty-updates Release Get:10 http:/ppa.launchpad.net natty InRelease [316 B] Ign http:/ppa.launchpad.net natty InRelease Hit http:/archive.ubuntu.com natty-security Release Get:11 http:/ppa.launchpad.net natty InRelease [316 B] Ign http:/ppa.launchpad.net natty InRelease Hit http:/archive.ubuntu.com natty/restricted Sources Get:12 http:/ppa.launchpad.net natty Release.gpg [316 B] Ign http:/http.us.debian.org stable/main Sources/DiffIndex Get:13 http:/ppa.launchpad.net natty Release.gpg [316 B] Hit http:/archive.ubuntu.com natty/main Sources Ign http:/ftp.us.debian.org etch/contrib TranslationIndex Ign http:/http.us.debian.org stable/contrib Sources/DiffIndex Get:14 http:/ppa.launchpad.net natty Release.gpg [1,502 B] Ign http:/http.us.debian.org stable/non-free Sources/DiffIndex Ign http:/ftp.us.debian.org etch/main TranslationIndex Get:15 http:/ppa.launchpad.net natty Release.gpg [1,928 B] Ign http:/http.us.debian.org stable/main amd64 Packages/DiffIndex Ign http:/ftp.us.debian.org etch/non-free TranslationIndex Ign http:/ppa.launchpad.net natty Release.gpg Hit http:/http.us.debian.org stable/contrib amd64 Packages/DiffIndex W: GPG error: http:/http.us.debian.org stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY AED4B06F473041FA NO_PUBKEY 64481591B98321F9 W: GPG error: http:/ppa.launchpad.net natty InRelease: File /var/lib/apt/lists/partial/ppa.launchpad.net_sunab_kdenlive-release_ubuntu_dists_natty_InRelease doesn't start with a clearsigned message W: GPG error: http:/ppa.launchpad.net natty InRelease: File /var/lib/apt/lists/partial/ppa.launchpad.net_ubuntu-wine_ppa_ubuntu_dists_natty_InRelease doesn't start with a clearsigned message E: Could not open file /var/lib/apt/lists/http.us.debian.org_debian_dists_stable_contrib_binary-amd64_Packages.IndexDiff - open (2: No such file or directory) output to: sudo cat /etc/apt/sources.list # deb cdrom:[Ubuntu 11.04 _Natty Narwhal_ - Release amd64 (20110427.1)]/ natty main restricted # See http:/help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http:/archive.ubuntu.com/ubuntu natty main restricted deb-src http:/archive.ubuntu.com/ubuntu natty restricted main multiverse universe #Added by software-properties ## Major bug fix updates produced after the final release of the ## distribution. deb http:/archive.ubuntu.com/ubuntu natty-updates main restricted deb-src http:/archive.ubuntu.com/ubuntu natty-updates restricted main multiverse universe #Added by software-properties ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http:/archive.ubuntu.com/ubuntu natty universe deb http:/archive.ubuntu.com/ubuntu natty-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http:/archive.ubuntu.com/ubuntu natty multiverse deb http:/archive.ubuntu.com/ubuntu natty-updates multiverse ## Uncomment the following two lines to add software from the 'backports' ## repository. ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. # deb http:/us.archive.ubuntu.com/ubuntu/ natty-backports main restricted universe multiverse # deb-src http:/us.archive.ubuntu.com/ubuntu/ natty-backports main restricted universe multiverse deb http:/archive.ubuntu.com/ubuntu natty-security main restricted deb-src http:/archive.ubuntu.com/ubuntu natty-security restricted main multiverse universe #Added by software-properties deb http:/archive.ubuntu.com/ubuntu natty-security universe deb http:/archive.ubuntu.com/ubuntu natty-security multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. deb http:/archive.canonical.com/ubuntu natty partner deb-src http:/archive.canonical.com/ubuntu natty partner ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. deb http:/extras.ubuntu.com/ubuntu natty main deb-src http:/extras.ubuntu.com/ubuntu natty main deb http:/ftp.us.debian.org/debian/ etch main contrib non-free deb-src http:/ftp.us.debian.org/debian/ etch main contrib non-free deb http:/http.us.debian.org/debian stable main contrib non-free deb-src http:/http.us.debian.org/debian stable main contrib non-free deb http:/non-us.debian.org/debian-non-US stable/non-US main contrib non-free deb-src http:/non-us.debian.org/debian-non-US stable/non-US main contrib non-free Thanks But after removing Debian repositories still getting this error: W:GPG error: http://ppa.launchpad.net natty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 9BDB3D89CE49EC21, W:GPG error: http://ppa.launchpad.net natty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 80E7349A06ED541C, W:GPG error: http://ppa.launchpad.net natty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8C851674F96FD737, W:GPG error: http://ppa.launchpad.net natty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 94E58C34A8670E8C, E:Unable to parse package file /var/lib/apt/lists/partial/archive.ubuntu.com_ubuntu_dists_natty-updates_multiverse_i18n_Index (1) I actually tried this before, but i am always getting this error --Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv-keys 8C851674F96FD737 gpg: requesting key F96FD737 from hkp server keyserver.ubuntu.com ?: keyserver.ubuntu.com: Connection refused gpgkeys: HTTP fetch error 7: couldn't connect: Connection refused gpg: no valid OpenPGP data found. gpg: Total number processed: 0