This question already has an answer here:

While running the update at Ubuntu 14.04 LTS (Trusty Tahr). The following error is being encountered:

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/universe/binary-amd64/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/multiverse/binary-amd64/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/main/binary-i386/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/universe/binary-i386/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/multiverse/binary-i386/Packages  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/main/i18n/Translation-en  Hash Sum mismatch

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/universe/i18n/Translation-en  Hash Sum mismatch

E: Some index files failed to download. They have been ignored, or old ones used instead.

command used:

sudo apt-get update

marked as duplicate by Seth Nov 26 '14 at 3:54

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up vote 97 down vote accepted

Enter the following commands in a Terminal:

sudo rm -vf /var/lib/apt/lists/*
sudo apt-get update
  • 16
    +1 for me. However, it would be great if you could comment why this issue happens. – ECII Nov 30 '14 at 13:23
  • 7
    see this answer for the root cause: askubuntu.com/a/160179/66329 -- TLDR: due to race conditions, your local repo cache can get into an inconsistent state; so delete it and apt-get update will refresh the whole thing from source – Justin Ludwig May 9 '15 at 20:17
  • 6
    after that i got "Failed to fetch archive.ubuntu.com/ubuntu/dists/trusty-security/main/… Hash Sum mismatch" – vuhung3990 Aug 2 '15 at 5:38
  • 13
    I fixed it using sudo apt-get clean; sudo apt-get update – Clayton Dukes Jan 11 '16 at 18:07
  • 2
    @ClaytonDukes After sudo rm /var/lib/apt/lists/* -vf, I repeated sudo apt-get clean; sudo apt-get update several times, then finally this issue is fixed. – Eric Wang May 4 '16 at 6:28

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