In the modern IT vernacular, the phrase “something has changed and I don’t understand what just happened” has usually been shorted into “virus”.
And as stated in the reply above, the heavily advertised tools are themselves too often somewhere between adware, problematic and insecure and vulnerable messes, and malware with a EULA.
The add-on security tools aren’t appreciably better than the built-in anti-malware (XProtect, XProtect Remediator, the read-only macOS volume, Gatekeeper and notarization, etc). And they can be noisy. Or worse.
Though sometimes the add-on security apps do do something so profoundly stupid that the built-in anti-malware blocks it.
Some security add-ons badly solve problems that haven’t existed for a decade or so, but badly solve the non-problem in a way perfect for collecting personally-identified metadata, too.
More commonly, the issues being reported — once we get past the “virus” description — are utterly benign. These can be cache corruptions, or software bugs, or nascent hardware problems, and such. On older Macs, failing hard disk drives get slow, and the slowness and the corruptions can get reported as “viruses”, as an example.
If somebody loads cracked apps, keygen tools, or bypasses gatekeeper and such, all bets are off.
There is certainly junk around (cracked apps, sketchy security apps, traditional malware, etc), so it’s possible this is malware. But then a whole lot of malware also gets directly and deliberately installed. So is it really malware?
What to do?
Please post the Etrecheck data.
I’d probably also reboot through Safe Mode, to rebuilt the icon caches.
