As Windows NT workstations become more entrenched in enterprise-critical and even mission- critical applications, the dependability of the Windows 32-bit (Win32) platform is becoming critical. To date, studies on the robustness of system software have focused on Unix-based systems. This paper describes an approach to assessing the robustness for Win32 software and providing robustness wrappers for third party commercial o_-the-shelf (COTS) software. The robustness of Win32 applications to failing operating system (OS) functions is assessed by using fault injection techniques at the interface between the application and the operating system. Finally, software wrappers are developed to handle OS failures gracefully in order to mitigate catastrophic application failures.