Q: how  cashew do i stop the opening page of mac adware offers to stop?

Stop pop-up ads in Safari - Apple Support

Quit Safari, then open it again while holding a Shift key when launching it from Applications or the Dock. Hold the Shift key down until Safari opens, and then release the Shift key.

That action prevents Safari from reloading the last pages that were open.

Hello philippalldino,

I wrote a little diagnostic program to help show what adware is installed. Download EtreCheck from http://www.etrecheck.com, run it, and paste the results here. EtreCheck is perfectly safe to run, does not ask for your password to install, and is signed with my Apple Developer ID.

If adware is installed, EtreCheck will help you remove it, although you may have to supply a password. If you aren’t comfortable with that, just post the EtreCheck report here and other helpers can tell you exactly what files need to be deleted and how to do so.

Disclaimer: Although EtreCheck is free, there are other links on my site that could give me some form of compensation, financial or otherwise.