It keeps taking over pages even if they do load. I end up having to click on the back button mltiple times because it keeps insisting that the page is missing when I can see it perfectly fine before it redirects it half a second later.

It will be better if this extension have a auto show option

This extension worked great for a long time, only showing the 404 detected popup when I actually encountered a missing page. However, I recently updated from Firefox 56 to Firefox 63 (which may have updated the extension too), and that caused the extension to start detecting spurious 404s, as other reviews describe. When this extension works, it is a convenient way to open the WayBack Machine, but I’m going to have to disable the extension for now until it gets fixed.

On older Firefox versions I used to use the add-on Resurrect Pages by Anthony Lieuallen. I stopped using it because it became incompatible with my Firefox version, but apparently it supports the latest Firefox version again. It may be worth checking out.

Too damn keen on redirecting working sites - Iv'e disabled it now until it's fixed

Too damn aggressive, if it has a pop-over that I can close I would be very happy but to just cause it to move away from the site I'm viewing because an image gives a 404 status is damn right WRONG.

This thing i turned off until it is revisited that it checks for the base path to return a 404 and ignores if the original request returns a status of 200. How damn hard can it be?!

It keeps making it impossible to visit working sites by redirecting me to a page claiming they're dead. There really should be an option to disable the automatic redirection

Great in principle, but... as plenty of other users have noted, it's way too hasty in execution. I'm continually having to reload perfectly live, current pages because it's jumped in prematurely. As others have also pointed out, it's ludicrous that the obstructive pop-up can't be cancelled – all it needs is a 'Cancel' button.

As a lot of people noted, too eager to display page that will take you to archives. Please, at least make setting that would disable that pop-up. I'm totally fine going into menu and asking for archive page from there if the page doesn't load. What I'm not fine with is when pop-up blocks otherwise working page.

Ask me to see archives when the site is good.

Works perfectly, I never found a problem with it and it helped me uncover some deleted pdf files.

Sometimes overreacts when page loads for a long time. I would prefer to not get modal dialog blocking page that loads correctly.

So far it's alright, and it does what it says on the tin. However, it is probably too eager to prompt the user to check the 404 page. On many occasions where the page did load, its modal window pops in my face asking me to check out any archived versions.

Worse still, the popup is a modal window that blocks out the rest of the page and cannot actually be exited out of without reloading the whole page.

Personally, I think it would be fine if there was no pop-up at all. Simply have the user access the toolbar button.

Seems to overreact with resource loading errors within the page.

This is not really properly tested.

This addon absolutely has some use in concept but it takes over pages loading slowly or differently - even fast loading consisten pages on some websites I visit.

I wish it worked, I wish there was a minimum configurable timer, and I wish I could set it to ONLY come up on ACTUAL 404's.

Instead, I'm just going to disable it for now and see if it ever gets better. Sadly it is far more in the way than helpful.

Have been using this since it was a Firefox Test Pilot project called "No More 404s". Never had any problems with it. It's one of those features that should be built into Firefox.

It's nice to be able to look up or save a page from the button. The automatic feature might be helpful if it was not a false positive 95% of the time. An option to turn that off would be worth a star to this review.

it seems overzealous, maybe an error loading some part of the page triggers the extension to assume the entire page is unreachable? that's my guess- I'm not sure exactly what is triggering the false positives exactly. has worked a few times as intended/expected, too

Often shows some giant wayback image for urls that are working. Actually it seems to think that there is an dns error while there is none. Not usable in this state.

Please only hijack the error pages (404 and dns error) and provide a link there to the wayback machine. That would be perfect. And thanks for wayback machine.

Constant false-positives, causing the giant Wayback Machine image to appear over an otherwise valid, working page, and causing me to loose all of my forward navigation history. Had to remove due to this extreme annoyance. Instead, it should simply show an icon in the address bar when an archived version of a page is available.