All the other messing about with Malwarebytes etc is a waste of time. Malwarebytes Premium is an antivirus replacement, protecting you and your devices from malware, ransomware, viruses, adware, spyware, malicious websites, and more. Your comprehensive defense against established and emerging threats. You have two choices: Either you update to at least Yosemite (10.10) with a more up to date and supported version of Safari or you stop using Safari as your browser and use Firefox or Chrome instead. Malwarebytes Premium for 10 devices, 1 year subscription. That message that keeps popping up is Safari warning you that its certificate for is out of date and it will appear everytime you go onto eBay and other sites that link to. Apple wants you to update to its newest version of macOS. Because the version of Safari on Mavericks 10.9.x is outdated, the security certificates that allow it to link to certain sites have expired and Apple is not renewing them. It is an adserver that certain websites, including eBay, link to. is not a virus or an ad popup so all the usual suggestions will not work. One of the responses on Apple discussion was interesting and here it is below: Someone mentioned that they tried 1.3.1 and they are still having the same problem. So you are protected and your machine keeps running silky smooth. I went on Apple discussion and within the past week there are over 300 complaints regarding the same problem. Proven Malwarebytes technology crushes the growing threat of Mac malware.
