How to block "Wellhello popup banner"

How to block pop-ups in Safari - Apple Support

You may have to delete website data (thereby also deleting cookies that are useful – but that is a small inconvenience for a clean browser).

Download this program which was written by Thomas Reed, a long time poster. The program will do the work for you which makes it easy. There is no reason to leave it installed once troubleshooting is finished. The free version doesn't update itself. If you need it again, you can download it again.

Malwarebytes Anti-Malware for Mac 10.10 and later

Malwarebytes uninstall

Did you try Malwarebytes?

Try running this program in your normal user account, then copy and paste the output in a reply. The program was created by etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy Report” and then paste into a reply. This will show what is running on your computer. No personal information is shown. You can run the report for free at least once, but if you run it several times, at some point it will ask you to pay a license fee.

Etrecheck – System Information

Most long time posters recommend not using antivirus software or cleaning software such as CleanMyMac.