This could be an issue caused by AdAware or Web Companion from Lavasoft.

You can look for a file named dsengine.js in these locations. You should only find channel-prefs.js in the "defaults\pref" location. Any file found here apart from channel-prefs.js is suspicious. You can check the content of the file in a text editor (use open with and do not double-click the file).

C:\Program Files\Mozilla Firefox\defaults\pref\ C:\Program Files (x86)\Mozilla Firefox\defaults\pref\

You can look for a file named dsengine.cfg in the main Firefox program folder.

C:\Program Files\Mozilla Firefox\ C:\Program Files (x86)\Mozilla Firefox\

Delete the dsengine.js and dsengine.cfg files when present.

Please finish off with https://www.malwarebytes.com/mac/

I could find no such files. Do the images here help figure it out about Yahoo?

Hi, by the looks of it you have a Yahoo Toolbar installed since November last year. Did not Malwarebytes pickup the toolbar ?

Not sure where you got the files from, if it s a Extension disable it. If it is installed some where I am not a Mac person, but with Windows it does have a uninstaller as it is a legit thing and is asked when you exit mail or start reading some articles on Yahoo. Had not seen it in a while.

Not to much on it from sites I would not trust. But this is reply from someone on Apple Forum : Yahoo Powered Search in my applications folder. Moved it to Trash.

You would know better than I.

It is not in extensions, only what I first posted is there. Nothing comes up with Yahoo word search in a new finder window, in the computer. No simple fix there. I have a macbook 12", and doing a word search the same way and in the same place, brings up only a duckduckgo page search results. So it is only in this machine. I'll keep tinkering. Where do you see a Yahoo toolbar installed in the images? I'll look more closely. Uninstalling some things with a Mac is just dragging it to the trash (and emptying trash, of course)

I see it. Should I get rid of yahoo.js also? How about Lightening.js?

When I did a search on {635abd67-4fe9-1b23-4f01-e679fa7484c1} -- which is what the Firefox, Resources, distribution, extensions has as a folder, with its defaults, preferences containing the yahooToolbar.js -- there were topics on line about it possibly being some kind of malware, and unpredictable, etc. But I don't know much. Maybe, I should just do a clean re-install. Maybe, I should open up all the folders and do screenshots for Monzilla, in case anything can help them.

Here are all the Firefox folders opened that are in my macbookpro 15" 2012 retina, in case Mozilla support can use the information. I wonder where I got the malware (if that's what it is).

Hi, no it is a legitimate program. Is fin if you like Yahoo and get Bing results. So it is just a PUP, potentially unwanted program.

Yes, drag anything with yahoo to the trash. Some stuff will remain but should not work if you get rid of enough.

You appear to be using a special third-party Firefox version with the update channel: "release-cck-yahoo" that is likely causing this issue. See on the "Firefox -> About Firefox" and the "Help -> Troubleshooting Information" (about:support) page.

I advice to uninstall Firefox (drag to the trash) and reinstall the current release.

You can find the full version of the current Firefox release (61.0.1) in all languages and all operating systems here:

• https://www.mozilla.org/en-US/firefox/all/
• https://www.mozilla.org/en-US/firefox/61.0.1/releasenotes/

Thanks for this feedback. It helps a lot. I gave it a 'helpful' click, but it does not show, now.

I deleted all firefox folders and icons, twice, putting them in trash then emptying permanently. Both times, when I reinstalled Firefox by clicking on the new download, it created a Firefox browser with the same bookmarks, history and settings as previously, including the Yahoo predominance even though it is not chosen in the Firefox preferences.

Hi, did you try https://www.malwarebytes.com/mac/ ? Did you get a new version as cor-el said from the URL ?

Ttry a Refresh but Note that this does more than uninstalling and re-installing does. Normal uninstalling does not remove some preferences which may have become corrupt. Please Refresh but do this 1st:

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

then

• https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...:

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

If is your Profile :

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Great feedback, and I will spend the evening going through every step, carefully. I'll get back to you guys, tomorrow. Thanks, again.

Using the link from cor-el's post, I downloaded a new Firefox at https://www.mozilla.org/en-US/firefox/all/ both times. I will work on your suggestions, now. more later...thanks...

I downloaded a beta trial of malwarebytes and it ran a scan, showing 2 threats about ad something or other. It corrected that, but the Yahoo thing remained. Onto the next thing to try.

I could not find the import/backup option in the library.

I went ahead and clicked on all the bookmark folder names listed under star Bookmarks, so all the individual bookmarks showed. I clicked on one, then selected them all, and while they were highlighted in all bright blue, I did a click on the trackpad and control to do select making a copy. (I don't use a mouse, so maybe it's a right click thing.) I just did a paste into Word, and all the bookmarks ended up being hyperlinked 'live'. Most of them are not crucial, so this will work for reference purposes. Off to try the next step.

I refreshed it, then the Yahoo thing disappeared. I made DuckDuckGo my main search and added the little search bar at the top with options in the preferences. Everything is working well, again. To summarize, this is what I did, as far as I can remember, from your suggestions.

1. Delete all Firefox folders in the computer and trash them. 2. Reinstall with a download from https://www.mozilla.org/en-US/firefox/all/ 3. Give https://www.malwarebytes.com/mac/ a once through at some point. The malwaresbytes did not get rid of it in this situation. It did get rid of two ad something or others, though. So, maybe, it is necessary for a partial clean out. 4. Keep checking to make sure the unwanted [automatic Yahoo in my case] is still there. 5. Select and copy all bookmarks from side menu, then paste into word processing document, i.e. Word, etc. 6. Refresh from https://support.mozilla.org/en-US/kb/refresh-firefox-reset add-ons-and-settings

Thanks to both of you!

There might have been some prefs changed by the previous Firefox version you had that were removed by the refresh.

I assume that you now see the correct "Update channel: release" on the about:support page?

Do you remember where and when you got that Firefox Yahoo branded Firefox version?

I noticed that I had an extra Firefox file document named Firefox2 that was dated 2014 when I clicked on it to see its contents. I deleted it with the other current release I had downloaded and slid into the computer's folder icon to install, and trashed it also. I found an interesting 2014 article about a possible Firefox use of Yahoo as default search for an upcoming release, if that indicates anything. I, also, have an email with a Firefox confirmation with an amazonses in its email sending history, if that indicates anything.