Despite what others keep saying, this add-on was NOT disabled because of a Firefox update. The problem is that they bizarrely (how it happened hasn't been revealed yet as of 4May2019-13:00) let a signing certificate expire.

This in turn caused ALL add-ons to be disabled because when they were checked for compliance with Firefox's policies last night at midnight they were ALL flagged as "unauthorized" (or "non-compliant") add-ons.

A fix has been issued. Simply go to Tools (press the Alt button to see the menu at the top of the browser) > Options > Privacy & Security and scroll down to 'Firefox Data Collection and Use' and make sure a checkmark is in 'Allow Firefox to send technical and interaction data to Mozilla' which will un-gray 'Allow Firefox to install and run studies' which should then also have a checkmark.

Close and re-open Firefox. To see if the Hotfix got applied, go back to same section as before and click 'View Firefox studies'. You should see an entry about 'hotfix-update-xpi-signing-intermediate-bug-1548973•Active'.

Your add-ons should now be re-enabled and working.

For everyone who is giving this a low rating because it won't load in Firefox: Duck Duck Go Privacy Essentials isn't working with Firefox right now because extensions were automatically disabled with Firefox's latest update. It isn't the fault of this extension, but the fault of Mozilla (Firefox's parent) to foresee that their update would break the ability to use extension such as this one. According to Firefox, they are "working on a fix" to enable extensions again.

So please don't punish Duck Duck Go Privacy Essentials (a great extension) for something that Firefox did. Ratings are for how well an extension does what is says it will dom ease of use, etc.; problems downloading or installing (which can sometimes be PICNIC issues) should not be given low ratings, as there can be external causes for these issues. If you download this after Firefox fixes what it broke, it should work again, and work well.

stop blocking this. i like this add on. shame on you firefox!

The fact that it has helped me avoid hazardous sites and kept my computer virus free is the only reason it gets this rating. If you could update the plug-ins so i may use it again, that'd be swell.

Works for me. Firefox is becoming too controlling.

For those of you who want to keep using this and any other add-on that has not been "verified" yet by Mozilla, here's what Mozilla tells you to do, and I can confirm that it works. I'm on Firefox Developer Edition.

"Firefox Extended Support Release (ESR), Firefox Developer Edition and Nightly versions of Firefox will allow you to override the setting to enforce the extension signing requirement, by changing the preference xpinstall.signatures.required to false in the Firefox Configuration Editor (about:config page). To override the language pack signing requirement, you would set the preference extensions.langpacks.signatures.required to false. There are also special unbranded versions of Firefox that allow this override. See the MozillaWiki article, Add-ons/Extension Signing for more information. "

Firefox + DuckDuckGo, sangat sesuai...