From 2-spyware.com
Nmon.exe – the executable file that is identified as an undesirable program due to shady processes running on the system. This file is a part of the application that can be harmful or even malicious. The threat may run on the machine and sneakily alter settings, disable or add features, files, programs. All these functions create persistence and significantly lessens options for the removal and system repair. This file can be a serious trojan related to other malware and distribute the payload of a serious threat, but it also can be considered safe and related to a program that gets corrupted or somewhat affected without your knowledge.