Hello sunshinpv, That must be very frustrating ! Please read this article about that virus (scroll down to the for Mac users relevant part) : [https://howtoremove.guide/remove-naganoadigei-com-virus/] And you may also want to take a look at [https://www.google.nl/search?authuser=0&ei=FlgbXKOmIJDWwQLK3Y3IAg&q=in+firefox%3A+how+to+get+rid+of++%60naganoadigei%60+virus+on++Mac+OS++%3F&oq=in+firefox%3A+how+to+get+rid+of++%60naganoadigei%60+virus+on++Mac+OS++%3F&gs_l=psy-ab.3...99534.107301..107667...1.0..0.143.1105.14j1......0....1..gws-wiz.......33i160j33i21.yT2S9mPpSG4 these other search results ......] Would you go to the Firefox menu => Preferences => Add-ons => Extensions, and remove anything that looks unfamiliar or suspicious. Then please read this article : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware It's important to run all malware scans that are listed in that article - what one doesn't pick up, the other one will. 'Hope this will help you get rid of the nuisance .....

Well said.