Even as a legacy tool, SolidWorks 2012 offers a robust suite of tools that cover most mechanical design needs:
Most "Portable" versions found online are created by third parties and hosted on unofficial sites. These files can often contain malware, keyloggers, or trojans. Solidworks 2012 Portable
Because it wasn't designed to be portable by Dassault Systèmes, you may experience "Blue Screen of Death" (BSOD) errors or lose unsaved work during a crash. Even as a legacy tool, SolidWorks 2012 offers