is a legacy masking plug-in for Adobe Photoshop designed to extract complex objects like hair, smoke, and liquid with high precision . While it was once a staple for photo compositing, it is now considered abandonware and is no longer officially sold or supported by Corel. Availability and Download Sources
If you see errors like MSVCRT10.dll missing or MFC42.dll not found , you need to install legacy Visual C++ Redistributables. Corel KnockOut 2 is a legacy masking plug-in