If you already have a license and need to find or enter your key:
Go to Help > Enter Key within the application.
If you lost your purchased key, you can use the Scooter Software Key Lost Tool to recover it.
Beyond Compare offers a that only counts days you actually use the software. Duration: 30 days of actual use. Features: Access to all features (Pro and Standard).
Many keys shared on forums (like GitHub Gists) are quickly blacklisted and will stop working when the software checks for updates.
Download links on crack sites are notorious for containing spyware or trojans that can compromise your personal data. Buy Beyond Compare