I have also a problem with Phoenixminer 5.8c.
I downloaded it from here and it worked fine. But after the reboot I clicked the shortcut and Defender announced 2 Trojan Viruses and blocked version 5,8c.

I have also version 5,5 installed and it works, but says, that OPenCL driver is of unknown version.

I have added 5,8c to Defender exceptions and corrected the Firewall also, but nothing has changed.

I am working now on 5,5 version, but 5,8 was better (less invalid and stale shares and more stable)

How could I fix it?