Please update to Firefox 61.0.2. Firefox 54 is no longer supported.

Then, what extension are you trying to install? Please give some more context if you still see this issue.

Hi FredMcD, extensions built on the WebExtensions APIs have much more restricted access to your system than legacy extensions. To read/write areas of the hard drive outside of extension storage, or to execute functions of companion software, an extension author may distribute a program that needs to be downloaded and installed separately from the extension. These separate programs do not get any review by the Add-ons team, so you should only install such programs from developers you trust and with a good understanding of what they do, as you would with any other applications you install on your system.

Fred, probably a dumb question, but are you trying to install this extension :

https://addons.mozilla.org/en-US/firefox/addon/nodejs/  ?

Tyler Downer said

Then, what extension are you trying to install?

I don't know. This started showing up about a month ago mostly when I try to download torrents

McCoy said

are you trying to install this extension? nodejs/

No

Ok, please update to Firefox 61, and then run a www.malwarebytes.com scan

Buy malwwarebytes .com for $299! To purchase, call +1 855-???-????0 or click here to BUY NOW!

Ah, good catch :) typos

I have already run SUPERAntiSpyware, Spybot-S&D, and Norton 360.

@ FredMcD and Tyler Downer :

Please, remove those links to 'Malwarebytes-with-the-extra-w" - it leads to a dangerous page  !

Fred, you can download Malwarebytes for free from here :

https://www.malwarebytes.com/

Oh, typo ......

I thought you guys were serious  :(

Malwarebytes is running now.

Note: I got the "One last step" page when I tried to download the installer. I have learned that the interrupted download can be restarted. A slight annoyance.

FredMcD said

Malwarebytes is running now. Note: I got the "One last step" page when I tried to download the installer.

Fred, I'm just curious : what are you trying to install and from where  ?

And where does 'NodeJS' come in (your header .... )

FredMcD said

Malwarebytes is running now.

After an hour, Malwarebytes showed me a list of Pup's and I quarantined them. But the issue remains.

However, I found the cause. It's the program; Free Download Manager. Disabling this removed the problem. I will have to contact its support.

McCoy said

what are you trying to install and from where  ?

Looks like any download causes the issue.

And where does 'NodeJS' come in (your header .... )

That's what the page is called.

FredMcD said

However, I found the cause. It's the program; Free Download Manager. Disabling this removed the problem. I will have to contact its support.

The reviews of that add-on are all bad .....

The first review :

"Using firefox quantum 61.01. When this addon is activated I notice continued outbound connection attempts to coinhive.com. Coinhive is a Trojan Data Miner that severely compromises your compuer. When this addon is deactivated the connection attempts stop. Draw your own conclusions but the addon does not function with Firefox Quantum other than to attempt this connection. Google coinhive.com for further details."

I haven't heard of that, and I've been using the program for years.

See also:

• https://en.wikipedia.org/wiki/Node.js

Thank you, everyone, for your help.

It has been 3 months, and the problem came back. Even disabling FDM did not stop it, so I did more digging.

I finally discovered the problem was caused by this file; C:\Users\===user===\AppData\Roaming\Mozilla\Firefox\ Profiles\===profile===\extensions\ {93d91d5e-1272-42e3-8323-a830fe339ac5}.xpi

Removing this solved the problem. I did a web search using many engines, but could not find any information on this file.

Thanks again to everyone that tried to help.

Hi FredMcD, as you may know, a .xpi file has the structure of a .zip file. If you rename it from .xpi to .zip, you can look inside and see whether it has a manifest.json file at the top level of the archive, which usually indicates it was built using the WebExtensions technology. An install.rdf file typically indicates a legacy extension.