The normal vssadmin command can't delete shadow copy's of type "ApplicationRollback". To delete the shadow image get the Volume Shadow Copy Service SDK from Microsoft. That SDK contain the vshadow command which can delete the shadow copy. The vshadow command can do very powerfull stuff - indeed a very interesting command.
N:\>vssadmin list shadows
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001 Microsoft Corp.
Contents of shadow copy set ID: {047a3cb0-04fe-4298-bfe9-0124ec79410b}
Contained 1 shadow copies at creation time: 8/27/2008 2:51:14 PM
Shadow Copy ID: {0d456a73-e8f4-4695-b0dd-59e55c190753}
Original Volume: (D:)\\?\Volume{8a9334e5-c416-11dc-95ba-806e6f6e6963}\
Shadow Copy Volume: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy1
Originating Machine: appdkba795.corp.novocorp.net
Service Machine: appdkba795.corp.novocorp.net
Provider: 'Microsoft Software Shadow Copy provider 1.0'
Type: ApplicationRollback
Attributes: Persistent, No auto release, Differential
D:\vss_tools>vshadow -da
VSHADOW.EXE 2.2 - Volume Shadow Copy sample client
Copyright (C) 2005 Microsoft Corporation. All rights reserved.
(Option: Delete all shadow copies)
This will delete all shadow copies in the system. Are you sure? [Y/N] y
- Setting the VSS context to: 0xffffffff
- Deleting shadow copy {0d456a73-e8f4-4695-b0dd-59e55c190753} on \\?\Volume{8a93
34e5-c416-11dc-95ba-806e6f6e6963}\ from provider {b5946137-7b9f-4925-af80-51abd6
0b20d5} [0x00020009]...
