What part(s) of your Add-ons page are blank? Could you check each of the categories: Plugins, Extensions, and Appearance.

If they are all blank, have you tried Firefox/Waterfox's Safe Mode to see whether one of the add-ons might be causing the problem?

If that doesn't help, perhaps the program files were damaged during an update. You may want to reinstall using the full installer (wherever that can be downloaded for Waterfox).

Support for Waterfox-specific issues can be found here:

https://www.reddit.com/r/waterfox

Your Question Details > More System Details shows an old Flash plugin. You probably should remove that one. The official method is to run the Flash uninstaller to completely get all Flash off your system, then reinstall the latest version. But manually removing just the physical file usually works.

Some relevant links:

• Uninstaller: https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html

• New installers: https://www.adobe.com/products/flashplayer/distribution3.html

• To find the path to the old Flash 14 DLL, type or paste about:plugins in the address bar and press Enter, then search in the page for npswf64 to find your Flash plugins with the full path listed. Only remove the one unwanted file, as the various other files in that folder may be for Internet Explorer or general utility.

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the extensions.* files (e.g. extensions.json, extensions.sqlite, extensions.ini) and compatibility.ini in the Firefox profile folder to reset the extensions registry.

• https://support.mozilla.org/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
• https://support.mozilla.org/kb/Unable+to+install+add-ons

If you see disabled or not compatible extensions in "Firefox menu button/Tools > Add-ons > Extensions" then click the Tools button at the left end of the Search bar to check if there is a compatibility update available.

If this hasn't helped then also delete the addons.json file.