Lately there are some new malware infections popping up, you might see them as chumsearch or weknow.ac, etc.
The best way to remove them is a little involved, but you can do it yourself.
First, run the Scan using malwarebytes.
Second, go to System Preferences>Profiles. If there are any profiles there called AdminProfile or Set Search, delete them.
Third, and this is where you have to have patience, you are going to have to manually look through the following folders in the main Library folder and also in your user Library. Here’s a list of folders to check:
ApplicationSupport, Caches, LaunchAgents, LaunchDaemons, Preferences, PrivilegedHelperTools, StartupItems. What you are looking for in any of these folders is anything that looks like installmac, installsearch, chumsearch, searchprotect, etc. If you see anything like that delete it.
You should also look in your Applications folder for the same kind of things.
After you’ve deleted anything weird, do a restart and the run Disk Utility>First Aid for good measure.
Good luck and let me know what you find.