Inaccessible Snapshots: Possible MachineState management bug?

[Bob]

host: CentOS 5.3 (64 bit)
guest: fedora 11 (64 bit)
Virtualbox: 3.0.4
Hardware: mostly intel

I'm having problems with a VM which is currently in an un-runnable state. Run from the GUI, it simply disappears after a moment (the GUI survives, but the "run" arrow greys out; from VBoxManage:

VBoxManage startvm scteachplate
VirtualBox Command Line Management Interface Version 3.0.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

Waiting for the remote session to open...
ERROR: Virtual machine 'scteachplate' has terminated unexpectedly during startup
Details: code NS_ERROR_FAILURE (0x80004005), component Machine, interface IMachine, callee <NULL>

This wouldn't matter too much if I could revert it, but any attempt to discard or revert a snapshot from the GUI results in (randomly) one of three things:

  1. the VM becomes greyed out, with a stop sign and "inaccessible". 
The "details" tab says: "The selected virtual machine is inaccessible. 
Please inspect the error message shown below and press the Refresh 
button if you want to repeat the accessibility check." (but a blank screen)
  2. As above, except that the screen _does_ contain a message, such as:
Result Code: Unknown Status 0x80000400 (0x00000400)
(since I can't find any doco on this, it doesn't seem to be much different from 1)
  3. VirtualBox segfaults

Running from VBoxManage gives:

VBoxManage discardstate scteachplate
VirtualBox Command Line Management Interface Version 3.0.4
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

ERROR: Cannot discard the machine state as the machine is not in the saved state (machine state: 1)
Details: code VBOX_E_INVALID_VM_STATE (0x80bb0002), component Console, interface IConsole, callee nsISupports
Context: "ForgetSavedState(true)" at line 1201 of file VBoxManage.cpp

This appears to originate from ConsoleImpl.cpp

    if (mMachineState != MachineState_Saved)
        return setError (VBOX_E_INVALID_VM_STATE,
            tr ("Cannot discard the machine state as the machine is "
                "not in the saved state (machine state: %d)"),
            mMachineState);

    HRESULT rc = S_OK;

    rc = mControl->SetRemoveSavedState(aRemove);
    CheckComRCReturnRC (rc);

    /*
     *  Saved -> PoweredOff transition will be detected in the SessionMachine
     *  and properly handled.
     */
    rc = setMachineState (MachineState_PoweredOff);

Am I right in guessing that the assumption built into the comment may not always be correct?

The system got into this state when the guest (fedora 11) hung during initial on-line update after installing OS and guest additions. I chose to turn the VM off (sorry, don't have a running VM right now, so I can't check the menu, but it's the last one on the list). I probably selected to discard the machine state, but I don't recall for sure.

Of course, any advice on how to rescue the VM would also be greatly appreciated...

[Frank Mehnert]

Please reopen if still relevant with VBox 4.0.4.