I expect you might be seeing disabled Legacy add-ons, or see that some of your add-ons were disabled after you updated to Firefox version 57. In Firefox 57, The WebExtensions API enables add-ons to be more secure and perform better with your browser. For more information, see Firefox add-on technology is modernizing.

Unfortunately not all add-ons were updated to this new standard. Visit http://arewewebextensionsyet.com/ to check if yours were updated. Mozilla also created a feature to help you find a replacement for your favorite add-on. Read more here.

To find replacements for your legacy add-on:

1. Click the menu button and choose Add-ons (or enter about:addons in a new tab).
2. In the Add-ons Manager that opens, Click Legacy Extensions
3. Click the Find a Replacement button next to your legacy add-on.

If a replacement doesn’t exist or isn’t helpful, please use this utility to find recommended alternatives. If you don’t find a suitable replacement, please head over to the add-ons forum for help. We expect legacy add-ons to continue migrating to the new WebExtensions standard, even if they missed the Firefox 57 release date.

There’s also a community-sourced list of alternatives on Google Docs.

Gent.le User 1929 I want to thank enormously because your answer has completely resolved my problem. Unfortunately I have seen that some addons are not compatible with version 57 of Firefox. That's why I will use yet version 56.0.2 until the problem of compatibility of addons will not be solved.

Sorry to have disturbed , thank you again, I salute you.

The biggest problem with the developers, etc. is forgetting that millions of users are NOT tech savvy. They want to get on the computer and use it. I want my Robo toolbar. I like classic theme restorer. Seriously wish people would listen to the forgotten users. It's like every time you put these updates into place, the most common response is this is what people want. What people? My mom who is 80? My husband? My kids? My friends? No. The day that someone comes up with a basic laptop with basic user capability is the day my mom can start using her laptop again. Shame you tech people just don't understand us.

I don't think that we older folks (I am 68yo and fixed cars for a living before I retired - not a computer professional) have been forgotten, it's just that "hanging on to the past" drastically limits Mozilla moving Firefox into the future and limits Firefox to becoming irrelevant on the modern web.

What you brought up (Roboform & Classic Theme Restorer) weren't ever part of Firefox and not a product from Mozilla. Both were 3rd party add-ons. The respective developers of those add-ons were who changed them drastically and in the case of CTR decided not to move forward and "killed" CTR - his choice.

There are "basic" laptops out there, you just have to "shop" for them on internet. Retail stores just aren't going to stock "basic" as the profit margin is generally too low for "bricks and mortar" operations to bother with.

But then with "basic", there is liable to be a huge learning curve for older users if they can't handle "change". Forget MacOSX or Windows operating systems getting installed on "basic" devices due to the cost. You end up with slim "off-beat" operating systems to suit each particular device and may end up replacing it rather than being able to update it. And manufacturer support is little to non-existent in many cases.

And many like the Chromebook is "tied" to the internet, so without an internet connection the user can't access their saved documents as most are "cloud devices" with little on-board storage capacity for user data.