As per Aaron's answer, the change is temporarily reverted due to the backlash, so the userscript is not necessary for now. To compensate for the loss in usefulness, I decided to add per-site user overrides (since 0.3.0) and allow it to work on the current 404 pages (since 0.4.0).

Screenshot / Code Snippet

Meta Stack Overflow 404 page

Custom user overrides:

Meta Stack Overflow 404 page with user override

The image is "The Black Beast of Aaaaaargghh" from the "Monty Python and the Holy Grail" film, 1975


The userscript brings back custom 404 pages to the Stack Exchange network replacing the lifeless corporate warning icon with community-specific images while preserving the updated layout. Currently supported communities (some 404 pages were never indexed by archive.org, so if you know of the missing 404 images, please let me know):

Community Image
Stack Overflow Stack Overflow 404
Meta Stack Overflow Meta Stack Overflow 404
Ask Ubuntu Ask Ubuntu 404
Super User Super User 404
English Language Learners English Language Learners 404
Code Review Code Review 404
Unix & Linux UNIX 404
Sci-Fi Sci-Fi 404
Math Math 404
Server Fault Server Fault 404
Ask Different Apple 404
Cross Validated Cross Validated 404
Arqade Arqade 404
Mi Yodeya Mi Yodeya 404
Home Improvement Home Improvement 404
Cooking Cooking 404
Crypto Crypto 404
Webmasters Webmasters 404
Chemistry Chemistry 404
Raspberry Pi Raspberry Pi 404
Emacs Emacs 404
Database Administrators 404
Graphic Design 404
Android Enthusiasts 404
Movies & TV 404
Software Recommendations 404
Academia 404

Change Log

v0.3.0 introduces per-site user overrides and a configuration modal accessed by clicking on a "404" button added to the main site menu:

site menu with config button added

The modal allows you to change the image source for each of the sites with custom 404 pages (ability to add sites to the list coming soon) - it will be loaded instead of the default image:

configuration modal feature

Since v0.8.0, there is a small icon next to each of the configuration labels - clicking on one takes you to the corresponding 404 page:

config item with icon link

Since v1.1.1, there the configuration modal supports custom header text as well:

config item with custom header input

Day-to-day changes:

Version Updates
0.6.0 options menu item is added for logged out users (or those without an account on a community) too
0.6.1 Added explicit support for the Greasemonkey userscript manager
0.7.0 Made modal draggable and made configuration modal load even on unsupported sites
0.8.0 Added quick links to 404 pages of each of the supported site
0.9.0 Added true cross-site configuration for Tampermonkey users
0.10.0 Added DBA, Android Enthusiasts and Graphic Design defaults
1.0.0 Deferred image replacement till "load" event; first major version
1.1.1 Added "Page not found" user overrides
1.2.0 Added Software Recs, Academia, and Movies & TV defaults
2.0.0 Switched to userscript manager-agnostic storage; fixed config item broken by recent UI updates


The script is licensed under the GPL-3.0-or-later license.


Install | Minified

The script doesn't need a userscript manager to work (but includes necessary headers).

Note that overrides are available cross-site only in userscript managers due to the nature of the same-origin policy.


Version number means "last tested on":

Chrome Opera Firefox Edge IE
✔ 92.0.4515.107 ✔ 77.0.4054.203 ✔ 89.0 ✔ 92.0.902.55 no

Userscript managers:

Greasemonkey Tampermonkey Violentmonkey
✔ 4.11 ✔ 31 ?


Author: Oleg Valter
Organization: UserScripters

Please, submit bug reports on the source repository.
Before adding a new one, please check if it hasn't been raised before.

You can also drop by to chat, we are a friendly bunch.


Source code written in TypeScript.

Contributions are welcome, you can always submit a PR here.

2 Answers 2


All Missing 404.

As far as I know, the 404s that have a black background, are transparent, but I am not sure.

  • I've tried each one, and it appears Stack Exchange added them back for these sites, so they work without the help of a userscript.
    – Anonymous
    Aug 4, 2021 at 17:36
  • 1
    @Anonymous yup, SE temporarily added those back after the backlash (see notice on the question). Thus to preserve usefulness til the day when they remove them again, the script now allows user customizations (using local storage, so be careful with private windows) Aug 4, 2021 at 17:42
  • @OlegValter How do you customize them?
    – Anonymous
    Aug 4, 2021 at 17:45
  • @Anonymous the script adds a menu item to the main menu (see the question for a screenshot of how it looks like or look for "404") which opens the customization modal on click :) Aug 4, 2021 at 17:55
  • @OlegValter That button doesn't do anything when I click it (or show anything in the console). This seems like a bug...
    – Anonymous
    Aug 4, 2021 at 18:07
  • 1
    @Anonymous done, seems to be an issue with GM restrictions - bumped to 0.6.1 Aug 4, 2021 at 20:28

Changing the .js prefix to .user.js would allow Greasemonkey to auto-detect that it is a userscript and install it by simply clicking opening the file.


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