Sean's blog

Ubuntu update problem: Failed to fetch … The HTTP server sent an invalid reply header

Ubuntu update problem - The HTTP server sent an invalid reply header

So you’re happily upgrading from Jaunty Jackalope to Karmic Kipper and there’s a network problem. A brief, normally completely recoverable network hiccup. Update-manager complains that it was interrupted, and quits. Thinking nothing of it, you start it again, and nothing works! The error messages are warnings like “W:Failed to fetch…” a few times, and then a last “E:Some index files failed to download…”.

I got confused by the files all having names like “Translation-en_GB.bz2”. I think this could problem could possibly be caused by having a transparent proxy cache between my PCs and the network. I’m wondering if there’s some issue with 404s / 304s being received by apt, or whatever it is that’s actually doing the HTTP work.

What fixed this problem for me was changing my repository in Synaptic to a different one, reloading the package lists, then changing back again to the original repository and reloading the package lists again. I don’t want to change repository because my Ubuntu PCs are all behind a proxy cache, which makes updates very much faster! I imagine the problem can be caused by any network problem – I had two today, one courtesy of my ISP, one courtesy of failing ethernet ports on an old router.

I couldn’t find anything with searching online that directly addressed this problem, though I found a few pages where people said they had the same problem. I hope you find this page quicker than I found the solution!