There are two distinct flavors of Windows 8. The first is for use on PC based systems and includes Windows 8, Window 8 Pro, and Windows 8 Enterprise. The second flavor is Windows 8 RT, which is for use on tablets.
Atrex 16, 17, 18
Atrex 16 newer are fully compatible with Windows 8 PC as a standard application. Atrex is NOT compatible with Windows 8 RT.
Atrex 13, 14, 15
Atrex 13, 14, and 15 appear to be incompatible with Windows Windows 8 PC as a standard application. Recent security updates have caused random errors with Atrex and in some cases the inability to start the application. Atrex is NOT compatible with Windows 8 RT.
Atrex 12 and Older
Older versions of Atrex, 12 and earlier, are incompatible with all versions of Windows 8 and are NOT supported on that platform even when run in compatibility mode.