Checking your Mac for malware presence
It can be rather difficult to hack into a Mac system but for experienced fraudsters nothing is impossible. Sometimes users install malware by mistake without realizing it. There are signs of malware being present on your PC. These may include unusual ads in your browser or your system works slowly. But don't fall into despair: everything can be fixed and your Mac will work as usual.
First thing you have to do is to see if there are any security updates. Chances are that you haven't updated security apps or other software and that's the problem why the PC is slowed down a lot. Check everything and update what is needed: click on the Apple menu and go to the AppStore. Select Updates section which is at the top part of the AppStore window. Update all the apps. Your Apple ID and password might be required to perform this action. If your PC is on macOS Sierra, switch on Automatic Install in System Preferences.
Other cases of problems with malware
If all the apps have been updated but the PC is still slow, you should do a check-up of the system. Click on App Store in the upper left corner of the Menu bar. Then select Preferences. If any apps found, that have never been downloaded intentionally, they must be deleted immediately. Sending them to the Trash bin is not enough; since this action will not delete all files connected to the app. Apps have their files in different places on Mac. You should use CleanMyMac X to trace them, check and remove.
Removing malware on PCs
CleanMyMac X software against malware may be downloaded from the Internet. Then, start it up from Applications folder. When it operates, look through the list of applications and find suspicious files that can be attached to the apps that you want to remove forever from your system. Put a check next to them. Press the Uninstall button and get rid of them forever.