Update manager is freezing in Utopic

[Zdenek]

Ubuntu 14.10 Utopic

When I run Update Manager it is freezing, process from ps aux:
/usr/bin/python3 /usr/bin/update-manager --no-update --no-focus-on-map

and the same is sudo apt-get update

Ign http://extras.ubuntu.com utopic/main Translation-cs
Ign http://extras.ubuntu.com utopic/main Translation-en
Mám:13 http://security.ubuntu.com utopic-security/universe amd64 Packages [44,9 kB]
Mám:14 http://security.ubuntu.com utopic-security/multiverse amd64 Packages [2 026 B]
Mám:15 http://security.ubuntu.com utopic-security/main i386 Packages [103 kB]
Mám:16 http://security.ubuntu.com utopic-security/restricted i386 Packages [8 438 B]
Mám:17 http://security.ubuntu.com utopic-security/universe i386 Packages [44,9 kB]
Mám:18 http://security.ubuntu.com utopic-security/multiverse i386 Packages [2 239 B]
Cíl http://security.ubuntu.com utopic-security/main Translation-en
Cíl http://security.ubuntu.com utopic-security/multiverse Translation-en
Cíl http://security.ubuntu.com utopic-security/restricted Translation-en
Cíl http://security.ubuntu.com utopic-security/universe Translation-en
100% [Čeká se na hlavičky]

Last row means "waiting for headers" and then nothing happens

[Zdenek (balderys)]

seems that http://cz.archive.ubuntu.com has problem with following packages

W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/universe/source/Sources Chybná hlavička [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/restricted/binary-amd64/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/universe/binary-amd64/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/multiverse/binary-amd64/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/main/binary-i386/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/restricted/binary-i386/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/universe/binary-i386/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic/multiverse/binary-i386/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-updates/main/source/Sources 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/main/source/Sources 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/restricted/source/Sources 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/multiverse/source/Sources 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/restricted/binary-amd64/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/multiverse/binary-amd64/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/restricted/binary-i386/Packages 404 Not Found [IP: 217.31.202.63 80]
W: Selhalo stažení http://cz.archive.ubuntu.com/ubuntu/dists/utopic-backports/multiverse/binary-i386/Packages 404 Not Found [IP: 217.31.202.63 80]
E: Některé indexové soubory se nepodařilo stáhnout. Jsou ignorovány, nebo jsou použity starší verze.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Zdenek (balderys)]

It also probably causes that Updates Manager cannot be opened when its icon is shown in Launcher