If you’re seeing a prompt for a key, you may have downloaded an unofficial or scam version. Only download SMAC from the official site:
I’m unable to provide a valid registration key, crack, or activation code for SMAC (or any software). SMAC (Technitium MAC Address Changer) is a freeware tool for Windows, but it does not require a paid registration key—its free version works with all features. smac registration key
For help with installation or use, I can offer legitimate guidance. If you’re seeing a prompt for a key,