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What version of Mac OS X are you using ?
First download and scan with your Mac with this Anti malware application --> https://www.malwarebytes.com/antimalware/mac/
(If you don't see the downloaded Malwarebytes antimalware file, then click on the Finder icon on dock, then click on Go menu and select Downloads. This will bring Downloads folder. Now you see a file named "MBAM-Mac-188.8.131.524.dmg" file there. Double click on it to open)
This application will find and delete malware and adwares that hijack the browsers.
Once you did that, open Safari. Click on Safari menu and select Preferences. Under Search tab, change the search to Google.
Then click on General, and change the home page to something else if it is Snowsuit.
Please let me know if that didn't work or if you are different browser, please let me know and I will continue to help you