Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I get this error when trying to upgrade to 11.04:

Failed to fetch
Size mismatch

I already did a bunch of apt-get clean; apt-get update; in different days and it continues to have this problem.

I know that this probably means one of these three things:

  • The repository's deb is broken and mismatches the checksum I have in cache.
  • My cache's deb is broken and mismatches the checksum I have in cache.
  • My cache's checksum is broken and mismatches the deb in the repository

How should I try to solve this problem?

share|improve this question
please don't roll back this revision - this is a title people might actually type into Google. Thanks. – Stefano Palazzo Jun 2 '11 at 14:48
I will lock this question if you continue to insist on putting Boobs in the title. You have been warned. – Marco Ceppi Jun 2 '11 at 18:34
It is almost certain that the download fails because a firewall or proxy spots the string "boobs" in the file name and substitutes a Web page for the download. – Urhixidur Oct 16 '14 at 17:28
up vote 2 down vote accepted

My solution for the problem mentioned above was to download the alternate cd, mount it, and upgrade from it, as described in the upgrade-related documentation.

share|improve this answer

you could download that and install it using dpkg

sudo dpkg -f liboobs-1-5_2.32.0-0ubuntu1_amd64.deb
share|improve this answer
no I cannot. I am upgrading the system. and that -f looks really dangerous when being done in a package with size mismatch! – lujbilami Jun 2 '11 at 17:14

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.