The phrase "With Key Reg" in the title refers to software cracks, keygens, or registry patchers. During the release of FL Studio 12, Image-Line had a robust online validation system. However, a wave of "key reg" tools flooded forums like AudioZ, RuTracker, and MacBed. These tools typically worked by:
It improved how the DAW handles 32-bit and 64-bit plugins through an updated wrapper, which was essential for stability on newer systems. The "OSX" Compatibility Problem Native macOS support did not officially arrive until FL Studio 20 Image-Line FL Studio updated to v12.0.2
Ironically, Image-Line later made FL Studio a much better value proposition. In December 2018, they announced that all FL Studio purchases would grant lifetime free updates . Furthermore, with FL Studio 20, they released a truly native 64-bit macOS version that did not require Wine. Today, the "key reg" scene for FL Studio 12.0.2 is largely abandoned because the official demo is feature-complete (only nagging you to restart every 30 minutes) and the full version is often on sale for $99.