In the interest of addressing your concerns in a timely manner I am going to assume you were able to restart your Mac in "Safe Mode" using the Terminal command I provided earlier, and were also able to revert that command successfully. If that's the case you can proceed below. If for some reason it didn't work please proceed anyway. You won't hurt anything by trying, but you may encounter difficulties carrying out the following instructions. If necessary, we'll figure out how to convince that Mac into booting Safe Mode some other time.
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First, ensure you have a reliable backup of your Mac, in case something should go wrong with continued troubleshooting. To learn how to do that, please read Back up your Mac with Time Machine.
- A backup is a fundamental prerequisite regardless of whatever method you may choose uninstall adware, and would apply even if your Mac were running perfectly well. Do not overlook this fundamental requirement. It's important.
Next: : Assuming you were able to, restart your Mac in Safe Mode again. Starting in Safe Mode takes longer than usual so let it finish. The popup created by that process will not appear in "Safe Mode".
The following files and / or folders need to be deleted while using your Mac in "Safe Mode", but if you were unable to restart your Mac in Safe Mode try them anyway.
First screenshot:
Third screenshot:
Nothing needs to be deleted from your second screenshot (which may have been either the User launch agents folder or the System launch agents folder, but presumably you know which one is which).
Drag those selections of files to the Trash. You may be asked to authenticate. Confirm they are no longer present in that folder. Leave all the others alone for now.
Next: open Safari and select the Safari menu > Preferences... > Extensions. If you see any Safari Extensions that you do not recognize or understand, simply click the Uninstall button and they will be gone. No Safari Extensions are required for normal operation. Then, select the General pane and review your Homepage selection. Repeat those equivalent actions for any other browser you may use.
There may also be adware-associated app icons in your Mac's Applications folder. Open it and examine its contents. Any unwanted or mysterious app icons should be obvious to you, but again please don't remove anything if you are uncertain—ask first. Identify any suspicious apps by name, or post another screenshot.
Next: In an abundance of caution, examine System Preferences > Extensions. Determine if there are any System Extensions that may have been installed without your knowledge. Ask if you're uncertain.
While you're there, check for the presence of any Profiles. Profiles are installed by organizations with a need to manage Macs deployed in institutional corporate or educational environments (for example), but have also been exploited by adware creators and similar malcontents.
Remaining within System Preferences, open Users & Groups. Select your User Account's Login Items. You may or may not find those Applications in its list. If you do, select them then click the [—] (minus) button to remove them from Login Items.
Next: You're finished with Safe Mode. If anything else needs to be removed it can be accomplished in normal mode (not Safe Mode). Please revert the Terminal command you used to invoke it as I wrote earlier:
sudo nvram boot-args=""
You can then restart your Mac and log in as usual. Confirm "Safe Boot" doesn't appear in the upper right of your screen.
Additional instructions to be continued in my next reply.