"Cracked" security software is a common vector for installing the very viruses you are trying to prevent.

Unofficial versions often cause system crashes or scan hangs. ClamXAV Antivirus Version History and Release Notes

You can download a fully functional free trial directly from the official ClamXAV website to test the software for 30 days without needing a registration code.

Cracked versions cannot access the official malware database updates , leaving your Mac vulnerable to new threats.