[SOLVED] What could make Synaptic suddenly start returning “Failed to fetch...” for any & all packages, from all repos?

[yellowfinch]

[Not sure about the translation of the quoted message. What I get is « W: Échec de la récupération de... », followed by the full URL of the .deb file it was trying to fetch.]

This is happening only on my LM 18.3 main machine.

Of course, I refreshed the cache. So, if a package is listed, why would the repo refuse to supply it?

The problem also affects mintupdate and mintinstall, as well as packages from PPAs, such as palemoon, which I used to be able to update just fine.

I wondered if this could be related to the disappearance of the quick filter function in Synaptic, so I booted up into a backup copy of the same 18.3 installation from about 6 months ago, when everything worked fine, and I now get the same error when trying to install or update packages.

In LM 17.3 and LM 19.2 on a test machine, on the same network, Synaptic still works perfectly.

Any hints would be much appreciated.

[sleeper12]

Just a guess, but try:

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 sudo apt update && sudo apt upgrade 

[yellowfinch]

Just a guess, but try: sudo apt update && sudo apt upgrade

Gulp!

Maybe I'll try that after my upcoming mid-month full backup, but even then it's not something I'm inclined to try on this mission-critical machine, especially without knowing more about “apt upgrade”. The doc says very little. It says that it “installs available upgrades of all packages”.

That would be the same as selecting all 5 levels in mintupdate and letting it update everything at once? If so, it would go against the recommendations found on the “Levels” tab of the mintupdate Preferences, such as: “Apply one by one. Impacts sensitive parts of the system” (about level 4).

[sleeper12]

Well, you could just do apt update & see if that helps any. Then you can just upgrade what you want.

[yellowfinch]

Well, you could just do apt update & see if that helps any. Then you can just upgrade what you want.

I've done “apt update” many times. That's what I meant by “I refreshed the cache”, in my initial post.

Since your reply seems to confirm what I was supposing (that “apt upgrade” is the same as applying updates through mintupdate), then we know that it won’t fix anything, because I get the same “Failed to fetch...” error whenever I try to upgrade any package through mintupdate.

[sleeper12]

Maybe mintupdate needs to be updated?

[yellowfinch]

Maybe mintupdate needs to be updated?

Maybe. But how can I? (The "apt" package itslef is one of the many I tried to update.)

[sleeper12]

If you click 'Refresh' in Update Manager, do you get an update for mintupdate?

[yellowfinch]

If you click 'Refresh' in Update Manager, do you get an update for mintupdate?

No, because I already have version 5.3.2.5. According to Synaptic, that's the most recent one.

[sleeper12]

Ok, I wonder if it has something to do with your /etc/apt/sources.list. If that's the case, someone else will likely jump in here.

[yellowfinch]

I wonder if it has something to do with your /etc/apt/sources.list.

For the record: my sources.list file is untouched since installation; it contains only a comment.

[sleeper12]

Ok, I have no other ideas then. Hopefully, someone else will.

[sleeper12]

If you had Timeshift set up before this happened, maybe you can use it to go back when things worked. Just a thought.

[yellowfinch]

If you had Timeshift set up before this happened, maybe you can use it to go back when things worked. Just a thought.

I do. I run Timeshift on the last day of every month and BackInTime on the 15th.

But I would have to know what to restore. Restoring everything as it was on 2019-10-31 would be similar to letting mintupdate upgrade everything, with regard to the risk of breaking something.

[squiggles3]

What this sounds like is you're not connected to the internet but I'm sure that you are if you are posting here? The fist thing I would try is changing my software sources, this won't help the issues with any PPA though. Revert back to the default sources or choose another mirror and see what happens. You can do this through the update manager by finding software sources in the menu.

Also,

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apt upgrade

only upgrades packages that have anything to upgrade to. So it is exactly like installing updates through the update manager, it's a safe operation unless you are specifically not upgrading a certain package for some reason.

[yellowfinch]

What this sounds like is you're not connected to the internet but I'm sure that you are if you are posting here?

That's right; no problem with internet access on the machine in question.

The fist thing I would try is changing my software sources

I had done that. (I tried two mirrors, other than the one I had always used.) That's what I meant by “from all repos”, in the title of this post. But I don’t know what you mean by “Revert back to the default sources”.

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apt upgrade

only upgrades packages that have anything to upgrade to. So it is exactly like installing updates through the update manager, it's a safe operation

Then why is there that warning in mintupdate, about doing level-4 updates one by one, for example? There are currently no level-5 updates pending for my system, but there are several ones in level 4, including “linux-firmware” (from 1.157.13 to 1.157.22). You would just let it throw that in with the whole lot?

[cliffcoggin]

You should apply all the outstanding updates available. The whole business of levels was a blind alley that Mint 19 has abandoned because it was misleading (with the best of intentions) most of us. If you are concerned about that just make a Timeshift snapshot beforehand so that you can revert to the previous state.

[ajgreeny]

I wonder if it has something to do with your /etc/apt/sources.list.

For the record: my sources.list file is untouched since installation; it contains only a comment.

What exactly do you mean by that?
Please show us the output of

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cat /etc/apt/sources.list

as you seem to be suggesting that the file has only a single commented line, ie one that starts with #, and is therefore just a comment, without any actual source lines.
Apologies in advance if I misunderstood.

[yellowfinch]

you seem to be suggesting that the file has only a single commented line, ie one that starts with #

You didn't misunderstand. It contains only this:

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#deb cdrom:[Linux Mint 18.3 _Sylvia_ - Release amd64 20171124]/ xenial contrib main non-free

What is it supposed to contain?

In another 18.3 installation, from a year ago, the sources.list file contains that same comment plus a PPA for some utility that I never installed on my current system. On a 17.3 system, there are also only comments in the sources.list file. Yet, Synaptic and mintupdate work fine on those machines.

I think you're on to something. I'd much rather try to fix a "source list" issue first, rather than the alternatives I've had to contemplate so far. However, as I replied to squiggles3, I don't know how or where a "default source" is supposed to be specified.

[yellowfinch]

Please show us the output of cat /etc/apt/sources.list

Okay, I found it in /etc/apt/sources.list.d/official-package-repositories.list :

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deb http://mirror.scd31.com/mint sylvia main upstream import backport 

deb http://mirror.clibre.uqam.ca/ubuntu xenial main restricted universe multiverse
deb http://mirror.clibre.uqam.ca/ubuntu xenial-updates main restricted universe multiverse
deb http://mirror.clibre.uqam.ca/ubuntu xenial-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ xenial-security main restricted universe multiverse
deb http://archive.canonical.com/ubuntu/ xenial partner

So, I see that these lines are the result of the selection I made in the two fields of the "Mirrors" section of Synaptic's config screen.

My usual official-package-repositories.list file would contain:

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deb http://mirror.csclub.uwaterloo.ca/linuxmint-packages sylvia main upstream import backport 

deb http://mirror.csclub.uwaterloo.ca/ubuntu xenial main restricted universe multiverse
deb http://mirror.csclub.uwaterloo.ca/ubuntu xenial-updates main restricted universe multiverse
deb http://mirror.csclub.uwaterloo.ca/ubuntu xenial-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ xenial-security main restricted universe multiverse
deb http://archive.canonical.com/ubuntu/ xenial partner

I can consult any of these in FTP mode, so there's no problem with accessing them.