DismUnmountImage function

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Unmounts a Windows image from a specified location.


HRESULT WINAPI DismUnmountImage(
  _In_     PCWSTR                 MountPath,
  _In_     DWORD                  Flags,
  _In_opt_ HANDLE                 CancelEvent,
  _In_opt_ PVOID                  UserData


MountPath [in]
A relative or absolute path to the mount directory of the image.

Flags [in]
The unmount flags to use for this operation. For more information about unmount flags, see DISM API Constants.

CancelEvent [in, optional]
Optional. You can set a CancelEvent for this function in order to cancel the operation in progress when signaled by the client. If the CancelEvent is received at a stage when the operation cannot be canceled, the operation will continue and return a success code. If the CancelEvent is received and the operation is canceled, the image state is unknown. You should verify the image state before continuing or discard the changes and start again.

Progress [in, optional]
Optional. A pointer to a client-defined DismProgressCallback.

UserData [in, optional]
Optional. User defined custom data.

Return value

Returns S_OK on success.


After you use DismCloseSession to end every active DismSession, you can unmount the image using the DismUnmountImage function.


hr = DismMountImage(L"C:\\test\\images\\myimage.wim", L"C:\\test\\offline", 1,
                    NULL, DismImageIndex, DISM_MOUNT_READWRITE, NULL, NULL, NULL);
hr = DismUnmountImage (L"C:\\test\\offline", DISM_COMMIT_IMAGE, NULL, NULL, NULL);


Requirement Description
Supported host platforms for WIM images DISM API can be used on any operating system supported by the Windows Assessment and Deployment Kit (Windows ADK). For more information, see the Windows ADK Technical Reference
Supported host platforms for VHD images Windows 7, Windows Server 2008 R2, Windows PE 3.0, Windows 8, Windows Server 2012, Windows Preinstallation Environment (Windows PE) 4.0, Windows 8.1, Windows Server 2012 R2, Windows 10, Windows Server 2016
Minimum supported client Windows 7 [desktop apps only]
Minimum supported server Windows Server 2008 R2 [desktop apps only]
Header DismAPI.h
Library DismAPI.lib
DLL DismAPI.dll

See also