title: VirtualBox guest won't start after Microsoft Update
body: <p>After a number of updates had been applied to my laptop running Windows 8 Enterprise the system started displaying the following dialog box when attempting to launch a VirtualBox guest:</p>
  
  <p><a href="https://i.stack.imgur.com/5YFVA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5YFVA.png" alt="Error Message after Microsoft Update"></a> </p>
  
  <p>The VBoxStartup.log reports the following:</p>
  
  <pre><code>1560.22e4: VirtualBox.exe: timestamp 0x550706a7 (rc=VINF_SUCCESS)
  1560.22e4: '\Device\HarddiskVolume4\Program Files\Oracle\VirtualBox\VirtualBox.exe' has no imports
  1560.22e4: '\Device\HarddiskVolume4\Windows\System32\ntdll.dll' has no imports
  1560.22e4: supR3HardNtChildPurify: Done after 593 ms and 0 fixes (loop #0).
  1560.22e4: supR3HardNtEnableThreadCreation:
  23c4.2198: Log file opened: 4.3.26r98988 g_hStartupLog=0000000000000004 g_uNtVerCombined=0x6223f000
  23c4.2198: supR3HardenedVmProcessInit: uNtDllAddr=000007f8de8b0000
  23c4.2198: ntdll.dll: timestamp 0x5507a832 (rc=VINF_SUCCESS)
  23c4.2198: New simple heap: #1 0000000000840000 LB 0x400000 (for 1822720 allocation)
  23c4.2198: System32:  \Device\HarddiskVolume4\Windows\System32
  23c4.2198: WinSxS:    \Device\HarddiskVolume4\Windows\WinSxS
  23c4.2198: KnownDllPath: C:\windows\system32
  23c4.2198: supR3HardenedVmProcessInit: Opening vboxdrv stub...
  23c4.2198: supR3HardenedWinReadErrorInfoDevice: 'ntdll.dll: 7981 differences between 0x300c and 0x4fff in #1 (.text), first: 4c != 1f'
  23c4.2198: Error -5600 in supR3HardenedWinReSpawn! (enmWhat=3)
  23c4.2198: NtCreateFile(\Device\VBoxDrvStub) failed: Unknown Status -5600 (0xffffea20) (rcNt=0xe986ea20)
  VBoxDrvStub error: ntdll.dll: 7981 differences between 0x300c and 0x4fff in #1 (.text), first: 4c != 1f
  1560.22e4: supR3HardenedWinCheckChild: enmRequest=2 rc=-5600 enmWhat=3 supR3HardenedWinReSpawn: NtCreateFile(\Device\VBoxDrvStub) failed: Unknown Status -5600 (0xffffea20) (rcNt=0xe986ea20)
  VBoxDrvStub error: ntdll.dll: 7981 differences between 0x300c and 0x4fff in #1 (.text), first: 4c != 1f
  1560.22e4: Error -5600 in supR3HardenedWinReSpawn! (enmWhat=3)
  1560.22e4: NtCreateFile(\Device\VBoxDrvStub) failed: Unknown Status -5600 (0xffffea20) (rcNt=0xe986ea20)
  VBoxDrvStub error: ntdll.dll: 7981 differences between 0x300c and 0x4fff in #1 (.text), first: 4c != 1f
  </code></pre>
  
  <p>The original solution was to uninstall Microsoft update KB3045999.  The guest would launch as expected - no more issue.</p>
  
  <p>Today however, after another set of Windows Updates was applied, the error has returned.  This time KB3045999 doesn't seem to be installed.</p>
  
  <p>Was KB3045999 rolled into a different update?  Is there a better fix/work-around available? </p>