After updating to Firefox 116.0.1, if you have noticed websites are not loading or working properly, check if you have the “AdBlocker Ultimate” extension installed in the Firefox browser.

Mozilla released Firefox 116 on August 1, 2023, with new features, improvements, and bug fixes. Following that, as usual, the company released a period update to fix minor issues it discovered in 116.

The recently released update Firefox 116.0.1 “fixed an issue which caused chart elements to render incorrectly for Windows users”.

Surprisingly, after installing this update, some users reported that web pages were not rendered or displayed properly.

It was also observed, YouTube doesn’t work or images from websites don’t load. Some users were unable to log in to websites.

Clearing the cache and cookies doesn’t resolve the issue.

Affected users were found to be running AdBlocker Ultimate Extension.

AMO reports, the adblocker has 2.1 million users, which is not a small user base.

The extension has not been updated for three months and the manifest.json does not mention the max version number it supports as 116, which could be an issue causing this.

[Update begins:

1. Visit Menu > Add-ons and theme> Adblocker Ultimate
2. Click on the three-dot menu and select Options
3. Click on Filters, and check for its updates by clicking on the “check for filter updates” icon on top.
   

On the 5th of August an invalid rule was live for an hour, and the users of AdBlocker Ultimate who updated to this rule had issues using some websites. The rule is fixed now and the tool can be used properly. Thank you all for reaching us and apologies for the inconvenience.

— AdBlocker Ultimate (@AdBlockUltimate) August 7, 2023

End of update]

Workaround:

If your Firefox is not working, check you have this extension installed and disable or remove the extension

1.  Click on the hamburger menu icon, select “add-ons and themes”
2. Disable the “AdBlocker Ultimate” extension
   
3. Install another content blocker, such as “Ublock Origin“.

II.

1.  Uninstall and reinstall Adblocker Ultimate. This has fixed the issue for some of the affected users.

Mozilla is aware of the issue.

Firefox 116.0.1 may have caused incompatibility between the extension and Firefox browser resulting in the issue.

If you’re affected and running above said extension, use the either of above solutions to overcome the issue.

If you’re not using Adblocker Ultimate and Firefox is not working, you may have to wait until Mozilla addresses the issue or see if downgrading to Firefox 116 helps..

More on Firefox:

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Firefox now supports adding images in PDF documents

How to disable Firefox’s ‘Some extensions are not allowed” Message