You won’t get the final CS6 updates (which fixed several bugs). Also, exporting to .MOV or .AVI may fail because QuickTime components are not registered.

Flash CS6 became Adobe Animate. It opens all old .FLA files perfectly. It exports to HTML5 Canvas, WebGL, and video—not dead SWF. A 7-day free trial or a Creative Cloud subscription (~$20/month) gives you a legal, working, modern tool.

Modern software (Adobe Animate) sometimes breaks older .FLA files, especially those using ActionScript 2.0. Flash CS6 Portable ensures 100% backward compatibility.

Many argue that since Adobe no longer sells Flash, it’s "abandonware." That is not how copyright works. Adobe still holds the IP. Distributing a cracked portable version is a violation of the DMCA. In corporate or educational environments, using such a download can get you fired or sued for license non-compliance.