So according to the Gospel of Spolsky 13:4, a core mission of Stack Exchange communities is to stop re-answering the same questions, and instead build a library of canonical answers. When general duplicates (instances of a problem) arise, we close and refer them to one such answer. For example:

bisig PPA causing 404 error? -> How can I fix a 404 Error when using a PPA or updating my package lists?

That said, many times on the review tab I see the same issues popping up, over and over... but don't know where to find the canonical question I know must exist! And should it not exist, that I know that we must make exist. Partial Upgrade errors anyone?

Please list common canonical questions that you know of in the following format. You can also answer with canonical questions you think should exist.

Is Jorge Castro a Robot?

Examples: How does Jorge Castro have so many badges?, I shook hands with a guy at UDS. Why was his hand cold and rubbery?, whiprush on internet - biology uncertainty

Queries: [if any, list data.stackexchange.com duplicate searches here]




**Queries:** DATA_QUERY_HERE [omit this line if no query exists]
  • 1
    I could see this page quickly growing out of control. There has to be a better way to maintain this information — dare I suggest a meta tag?
    – ændrük
    Commented May 13, 2012 at 20:16
  • I assumed moderators had a list somewhere that they passed around for such things. Is this not so? Is this question on meta meant to create such a list? Commented May 18, 2012 at 1:20
  • 1
    @Chan-HoSuh As I explained on chat, this is the canonical list. mods (like normal users) can (and do) maintain a personal list, but it's generally very specific.
    – jrg
    Commented May 18, 2012 at 1:48
  • I added a proposed bracket. I think desired, proposed, and accepted should all have lists. Commented Jun 15, 2012 at 4:09
  • Dare I suggest to categorize the proposed questions (as they have done in TEX.SX), and not to restrict the list to "how to"s? I think it would be useful to have also readily available links to things like "What is a PPA?" and such.
    – carnendil
    Commented Jan 18, 2016 at 6:56

6 Answers 6


Existing canonical questions:

Desired canonical questions:

  • How do I diagnose fan problems?

    Possibly multiplexes into other questions for specific, common hardware configurations.

  • How to fix partial upgrades error?

    Common, fairly annoying.

  • Installing Ubuntu failed. What should I do?

    Countless examples

  • How do I swap / remap keys?

    A variety of cases. System-wide versus application-specific. Swapping keys or altering the layout in some way. Solutions also differ. There are DE-specific solutions and general X-windows solutions. Sometimes these conflict, causing their own issues.

  • The system has frozen up, although the mouse still works. What should I do?

    Pointless to just tell them to file a bug, because ubuntu-bug alone doesn't capture the right information. There are specific troubleshooting steps to do in order to collect the required information, but what to do is also driver-specific. The Ubuntu-X freeze troubleshooting guide in the wiki is a good reference but users often need some additional hand-holding and encouragement.

  • The session terminated and left me at the login screen. What do I do?

    Basically, need a full backtrace collected via gdb; apport is supposed to collect this but in cases where it's come to a question, it probably has failed to do so. The Ubuntu-X Backtrace wiki page walks the user through how to do this manually but can be intimidating for less technically oriented folks.

  • My screen went blank and I can't turn it back on. What do I do?

    The symptoms for "black screen bugs" are always indistinguishably similar, but the underlying causes are quite varied. There are several dozen different distinct causes for blank screens, and it's worthless to guess based merely on reported symptoms. But simply filing a bug report is not usually enough either, since you need to look at the status of things both before and after to spot differences. The Ubuntu-X wiki pages have some guides on what to do here, but most users need extra hand-holding.

  • I upgraded and something stopped working right. How do I narrow down what exactly broke?

    Package bisection search time. /var/log/dpkg.log to the rescue!

  • 1
    What about my "How to port Ubuntu Touch to xyz device?" question - do you want that in this list? Commented Nov 10, 2013 at 21:00
  • I guess Canonical questions are useful if: 1) They provide links to as many related questions as possible (with the possibility of permanent update by users), as "Existing canonical questions" here; 2) They get listed high in searches (Google, StackExchange, etc.), so users can have it as a "reference index". Item #2 does not seem to happen, so I am not seeing this list very useful, as of today. Can this be worked out? Commented Oct 22, 2021 at 7:48


  • I broke my system by messing about with python. How do I fix it?
  • I used the directions on a website to install wine and broke my system. How do I fix it?
  • Pending Update of Snap Store / canonical answer https://askubuntu.com/a/1412580/243321
  • Why are packages being held back when I do an update / because of phased updates
  • 2
    Removed Python 3 and now Ubuntu Software Center, terminal and other applications don't work For "I used the directions on a website to install Wine and broke my system" it depends on the error message. There are two main categories of questions: 1. questions that contain a "you have held broken packages" error message and 2. all other questions that don't contain this error message. There are 4 or 5 questions that I use as duplicate questions for close voting Wine questions depending on the error message.
    – karel
    Commented Feb 6, 2022 at 11:59
  • 1
    Yep. See this question for another example of "I messed with Python and broke my system"
    – cocomac
    Commented Feb 23, 2022 at 22:00

I added a proposed bracket. I think desired, proposed, and accepted should all have lists.


Example suitable duplicate: How to deal with a frozen screen?
Proposed canonical answer: What should I do when Ubuntu freezes?

Rationale: Different than, How do I file a bug?, How do I troubleshoot what is crashing?, and their ilk, but has a good detailed answer.


Just thinking, do we have a Canonical answer for how to safely remove Ubuntu from a Double/Multi-boot? That would be useful I believe.

  • There likely already exists a answer along the lines of "boot off live CD, delete ubuntu partition, and reformat, or re-size the windows partition to over take the space."
    – virtualxtc
    Commented Jan 15, 2014 at 10:12

If we're in dupe or merge mode, this should probably be incorporated: Finding questions that other questions have been closed as a dupe of

Just saying, a list question that is unmaintainable is not a script that is maintainable.


Another CQ below.

There are different causes and solutions for this problem (and most likely for other CQs as well). But I guess what could be considered "Canonical" is the initial set of actions, commands to try, information to post in a prospective new question. This should be brought to attention immediately for anyone asking, I guess. See also this comment.

Only "Dummy output" (sound) in Ubuntu 20.04 after reboot - Broken driver / module

Examples: (out of the tons here)
Ubuntu 19.04 dummy output , Output device is dummy output , Ubuntu 21.04 dummy output , Persistent Dummy Output , Ubuntu 18.04 LTS dummy output , Ubuntu 19.10 Dummy Output error , No audio output in 18.04. Only output device is 'dummy output' , Dummy Output after upgrade to 16.10 , Sound stopped working, "dummy output" , Dummy Output Sound Error , Dummy Output help required , Dummy output, no soundcard detected , Dummy output for sound , Dummy Output Ubuntu 20.04 , ...

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