Right-click the installer and select Properties. Under the Compatibility tab, set it to run in Compatibility Mode for Windows XP (Service Pack 3).
If you need a more secure or actively maintained tool for production environments, consider these alternatives: Solved: 3Com's 3cdaemon Still Available? - Cisco Community 3cdaemon windows 11
: Use it only on isolated or trusted lab networks . Right-click the installer and select Properties