Acts too aggressive, often falsely, replaces the whole page instead of showing a popup or something unintrusive.

The “Page not available?” site opens even for some sites that work perfectly fine and prevents visiting these sites completely and this feature can't be disabled in favor of only manually visiting a site's archive.
Also the context menu entry only works for the current page, even if you right-clicked a link. I would've expected to be taken to the archive of the site the link leads to, but that could just be me.

As a Web Developer I have clients that come to me after losing their website to hackers, just need a redesign, or use to have a website but want to use data from that. Way Back Machine has allowed us to find content from way way back and we thank you for that.

Just like anything worthwhile, it takes learning how to use this "tool" correctly. Despite a few comments I've seen.....it's not hard to use if you spend some time to learn what it does and how to correctly implement it's abilities. I find, when I find NO results for an item I KNOW is out there, I just rename my search or change to text and it gives me all the answers to what I am looking for without having to guess or give up. Great app.

Very annoying, this add on keeps popup up and taking over webpages that are not down and normally would load fine. Sounds like others are having the same issue. I guess I'll have to remove this if the developers are not going to fix it.

This app is pretty useful when for some reason you want to access a link that is dead or you want to read posts from a specific time in the past. However I think this addon really needs a setting to specify how long it needs to wait until it pops up, as well as a website specific disable feature, as it often breaks CloudFlare protections, popping up before CloudFlare gets a chance to load. For some websites you can just close the popup, annoying but not a big problem, however on some sites, closing the popup forces CloudFlare to restart loading, the popup appears again, and it's an endless loop. Ideally it should have an option so it wouldn't even popup, and would have an option to only load Wayback Machine if I click the addon's icon.

I love this extension, but false positives in recent months have been really annoying, I sometimes needed to press Back up to five times to just be able to see the page I was reading.

As others already mentioned there's a bug where it thinks the page failed to load when it didn't. If you just provide the option to disable this auto detection it would be great.

As others have written, on recent Nightly versions there are many false positives where it thinks the page isn't available but it is.

Unconfigurable, which gets annoying if one doesn't want to automatically (or always) see the archived version.

Lately it seems way too quick to jump to a wayback lookup when clicking the 'back' arrow button on Firefox. I'm just jumping back to a page that I had just looked at! It isn't 404!