This documentation is archived and is not being maintained.

RegistrationServices.UnregisterAssembly Method

Unregisters the classes in a managed assembly.

Namespace:  System.Runtime.InteropServices
Assembly:  mscorlib (in mscorlib.dll)

public virtual bool UnregisterAssembly(
	Assembly assembly


Type: System.Reflection.Assembly
The assembly to be unregistered.

Return Value

Type: System.Boolean
true if assembly contains types that were successfully unregistered; otherwise false if the assembly contains no eligible types.




assembly is null.


The full name of assembly is null.


A method marked with ComUnregisterFunctionAttribute is not static.


There is more than one method marked with ComUnregisterFunctionAttribute at a given level of the hierarchy.


The signature of the method marked with ComUnregisterFunctionAttribute is not valid.


A user-defined custom unregistration function (marked with the ComUnregisterFunctionAttribute attribute) throws an exception.

UnregisterAssembly removes the registry entries for the types in the specified assembly previously added by RegisterAssembly. This method also calls any unregistration functions found in the assembly.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

  • SecurityCriticalAttribute 

    requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.