A Mac often exhibits one or more of the following symptoms if it has a virus or other malware.
Check out the Activity Monitor to see if something is taking up way more memory or CPU time than expected. If your Mac’s fan is making more noise than usually, it is an indication that your processor is very likely burdened. There are many other legitimate reasons for a computer to slow down, so slowness alone isn’t a dead giveaway you are infected by malware.
Check out whether your connection is slower when your Mac is on than when it is turned off. That might indicate that something malicious taking up your bandwidth – yet there could be other reasons, like App Store downloading large automatic updates. You can check your network speed easily with online speed testers.
Even macOS isn’t immune to crashing. If your Mac crashes often, something is wrong, and it could be either faulty hardware, some software messing up or even malware.
Internet is plastered with ads, no surprises there. However, if you see stuff popping up on your screen even when you’re not actively browsing, you might be infected with adware. Adware is a type of malware designed to display ads for malware creator’s benefit.
Your browser is the center of your internet activity, and this is why some malware targets that specifically. Malware can install toolbars on your browser or change your home page to lure you into doing something that gets the malware creator some referral marketing revenue. It could be worse – the malware might be spying on you and your login credentials.
Are there new files in system directories, or even your desktop directory that you have not seen before? Some malware leaves traces of itself on your computer when storing data.
Are you getting unexpected instances of odd windows popping up and vanishing? This might very well be a signal of malware making unauthorized moves on your computer.
Viruses are designed to spread. There are many mechanisms they use for that, and one is to use emails or instant messages (such as Facebook or Skype messages) to infect new people. If you hear that you have been messaging your friends weird links, it is very likely that you are infected by malware – or your account might be compromised. Or even worse – both!
If you suspect you have a virus or other malware, and you have an internet security suite such as F-Secure TOTAL, check that the software is up to date and run a full system scan on your computer.
If you have a virus, refer to the instructions your security suite gives you or see the general malware removal instructions.
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