Why is a Trojan not being detected on mcafee?

A Trojan may not be detected by McAfee if it is using advanced obfuscation techniques to hide its presence, or if it is a new variant that McAfee's virus definitions have not yet recognized. Additionally, the Trojan could be residing in a location that is not actively scanned by the antivirus, or it might be a false negative due to limitations in the software's detection capabilities. Regular updates and scans are essential for effective detection and protection against such threats.