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WaitHandleCannotBeOpenedException Class

The exception that is thrown when an attempt is made to open a system mutex or semaphore that does not exist.

Namespace:  System.Threading
Assembly:  mscorlib (in mscorlib.dll)

public class WaitHandleCannotBeOpenedException : ApplicationException

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.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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.

.NET Framework

Supported in: 3.5, 3.0, 2.0