id	summary	reporter	owner	description	type	status	component	version	resolution	keywords	cc	guest	host
8274	VBox 4.0.2 delete snapshot error with running VM	cdp-ava		"Host: Win7 x64
Guest: Win7 x32

Snapshots can be created via vboxmanage for the running image, but cannot be deleted while the virtual guest is running.  For example:

Microsoft Windows [Version 6.1.7600]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\dbear>cd ""\Program Files\Oracle\VirtualBox""

C:\Program Files\Oracle\VirtualBox>VBoxManage.exe snapshot Win7 take backup1
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

C:\Program Files\Oracle\VirtualBox>VBoxManage.exe snapshot Win7 delete backup1
0%...
Progress state: RPC_E_SERVERFAULT
VBoxManage.exe: error: Snapshot operation failed. No error message available!
-=-=-=-=-=-=-=
Once the guest is shut-down, the snapshot is then able to be deleted:
C:\Program Files\Oracle\VirtualBox>VBoxManage.exe snapshot Win7 delete backup1
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

"	defect	closed	VM control	VirtualBox 4.0.2	duplicate	snapshot		Windows	Windows