Instances of the Mutex class and the Semaphore class can represent named system synchronization objects. When you use the Mutex.OpenExisting method or the Semaphore.OpenExisting method to open a named system object that does not exist, a WaitHandleCannotBeOpenedException is thrown.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.