Are you sure it's an extension?

It’s very sad, but many software downloaders/ installers will trick you into installing not only their program, but other programs as well.

You have heard of the fine print in shady contracts, right? Well, some installers you need to look at the itsy bitsy teeny weeny fine print.

You are thinking you are giving the installer permission to install the program you want by using the recommended option. But if you use the Manual Option Instead, you discover all kinds of stuff that you do not even know what it is or what it does.

From now on, everyone needs to Use The Manual Option to put a stop to this.

Note that these programs can also change browser/computer settings.

It could be the add-on is hidden. Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh).

Now open the Add-ons Manager.

Type about:addons<enter> in the address bar. Hot key; <Control> (Mac=<Command>) <Shift> A)

In the Add-ons Manager, on the left, select Extensions. Make sure you know what each one is and what it does.

Thanks for these answers. I'm not sure what the Manual Option is! I hope next time I'm trying to get addons I can find it. Mostly I want addons to get PDFs of pages or Edit the Firefox menus to get rid of things I don't want.

I tried booting Firefox in safe mode but I didn't find anything I couldn't see when I looked at addons in regular mode. I read through them all and looked at their ratings and read the ratings if they were less than four star. I still couldn't find what this poison is, so it must not be an extension. I don't know what else could take over my Firefox. It's so irritating.

I read through them all and looked at their ratings and read the ratings if they were less than four star. I still couldn't find what this poison is, so it must not be an extension. I don't know what else could take over my Firefox. It's so irritating.

Well, it could be from a particular web pages or ad network used in that page. But I still think an extension is more likely.

Thank you for sharing your add-ons list, but I have never seen so many active extensions, so it’s difficult to research so many. I suggest if you test one and don't find it helpful, disable it immediately to avoid confusion/conflicts and risk to your privacy/security.

At least I can vouch for my own extensions (Content-Type Fixer, Printable - The Print Doctor, and Save webP as PNG or JPEG). ;-)

I don’t think any of these would be involved

• Adblock Plus - free ad blocker
• uBlock Origin
• SingleFile
• Translate Web Pages

Please disable everything that mentions PDF by clicking its slider switch:

• Kofax PDF Create
• Pdf Downloader
• PDF Mage
• PDF Wise
• PDFmyURL
• Print Friendly & PDF (ff-addon@printfriendly.com)
• Print Friendly & PDF (jid0-YQz0l1jthOIz179ehuitYAOdBEs@jetpack)
• Print PDF
• Print to PDF
• Save as PDF
• Save Page As PDF
• Save PDF
• save-as-pdf-from-context-menu
• WebToPDF

Note: Firefox has built-in print-to-PDF by changing the "Destination" to "Save to PDF" when you display the print overlay.

Any difference so far?

You might also want to disable everything that captures screenshots by clicking its slider switch (this might not be all of them):

• Easy Screenshot
• Easy Screenshot - a Web Clipper
• Handy Screenshot
• Nimbus Screen Capture: Screenshots, Annotate
• Page Saver WE
• Page Screenshot
• Screenshot
• Take Webpage Screenshots Entirely - FireShot

Note: Firefox has a built-in screenshot tool: Take screenshots in Firefox

Any difference so far?

I will check them. Some I've been using for ages and they're great. The hard thing is, it doesn't pop up constantly. So it's not like I can disable and know right away. I'll have to do them bit by bit and wait. Thanks for the good suggestions.