Software Updater fail, and "apt-get update" throws "Invalid operation update" - what next?

Question

I'm running a fairly vanilla 14.04 Ubuntu on a newish HP desktop. Just yesterday I got the dreaded "Failed to download repository information":

A screenshot of this window has been seen on AskUbuntu before. I have checked related threads here, and also looked at a helpful off-site article. The strange thing now is that when I run sudo apt-get update I get back E: Invalid operation update, so I can't even work out what the offending PPA is.

The Updater does find updates and apply them (you can see what I got today if you like), but that's little help in diagnosing the problem.

So my question: how do I fix this?!

Solution

Usually this error happens when you mis-type the apt command, which doesn't seem to be case here (if I believe you).

Can you please login as su and then do the apt-get update?

I know using the system as Super User is not a good thing to do but at lease for one time, you can give it a try.

P.S. Is there a proxy on your network?

Comments

[kenorb]

I had the same error, I've missed apt command to run (e.g. install).

[Cameron Taggart]

I've ended up here three times already when my shell script ends up having CRLF line endings instead LF line endings. Future self, just switch the line endings.

[Dɑvïd]

Finally had a chance to look at this - updating as "su" did the trick: I could identify the offending PPA's. I used the sudo -i temporary "su" login as described in the RootSudo documentation. Nice to have that sorted! :)