Here is a blog post exploring why users search for these keys, the hidden dangers of using them, and the legitimate ways you can actually get FineReader for free or at a discount.
While searching for "free fixed" license keys for ABBYY FineReader 15 is common, it is important to distinguish between official free trials and high-risk "cracked" versions found on third-party sites. Abbyy Finereader 15 License Key Free Fixed