Unable to start Virtualbox on Windows 10 after recent restart

This morning when I got to my Windows 10 PC, I had the banner overlay requesting me to restart because an upgrade needs to be completed. It appears this was the patch to build 10586.17.

I shut down my running VM, named 'mercury' and restarted the Windows machine to apply the updates.

A few hours later, I logged back into the windows machine in order to start the 'mercury' VM back up. At this point I discovered I was unable to start VirtualBox. I thought it might be because of some compatibility issues with the latest version of Windows so I downloaded the latest version of VirtualBox from www.virtualbox.org.

It installed successfully but I am still unable to start VirtualBox.

If I try to start the 'mercury' VM via the command line as follows:

cd "c:\Program Files\Oracle\VirtualBox"
VBoxManage.exe startvm "mercury" 

I get the following message:

Waiting for VM "mercury" to power on...
VM "mercury" has been successfully started.

The machine does not start however and in the VBoxSVC.log file (in .VirtualBox) I see the following:

VirtualBox COM Server 5.0.0 r101573 win.amd64 (Jul  9 2015 11:08:16)   release log
00:00:00.004001 main     Log opened 2015-12-08T07:24:26.755587800Z
00:00:00.004001 main     Build Type: release
00:00:00.004001 main     OS Product: Unknown NT v10.0
00:00:00.004001 main     OS Release: 10.0.10586
00:00:00.004001 main     OS Service Pack: 
00:00:00.018841 main     DMI Product Name:                                 
00:00:00.024345 main     DMI Product Version:                                 
00:00:00.024345 main     Host RAM: 8099MB total, 5325MB available
00:00:00.024345 main     Executable: C:\Program Files\Oracle\VirtualBox\VBoxSVC.exe
00:00:00.024345 main     Process ID: 4032
00:00:00.024345 main     Package type: WINDOWS_64BITS_GENERIC
00:00:00.026347          Home directory: 'C:\Users\Hendri/.VirtualBox'
00:00:00.026347          Loading settings file "C:\Users\Hendri/.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:00.340070          HostDnsMonitor: old information
00:00:00.341062            no server entries
00:00:00.341062            no search string entries
00:00:00.341062            no domain set
00:00:00.341062          HostDnsMonitor: new information
00:00:00.341062            server 1: 192.168.8.1
00:00:00.341062            server 2: 196.32.232.244
00:00:00.341062            no search string entries
00:00:00.341062            no domain set
00:00:00.341062          HostDnsMonitorProxy::notify
00:00:00.385419          VD: VDInit finished
00:00:00.386993          Loading settings file "D:\Virtual Machines\mercury\mercury.vbox" with version "1.15-windows"
00:00:00.387994          Loading settings file "D:\Virtual Machines\venus\venus.vbox" with version "1.15-windows"
00:00:00.388994          Loading settings file "D:\Virtual Machines\earth\earth.vbox" with version "1.15-windows"
00:00:01.879145 Watcher  ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={f30138d4-e5ea-4b3a-8858-a059de4c93fd} aComponent={MachineWrap} aText={The virtual machine 'mercury' has terminated unexpectedly during startup with exit code -1073741819 (0xc0000005)}, preserve=false aResultDetail=0
00:00:06.880525 main     ERROR [COM]: aRC=VBOX_E_OBJECT_IN_USE (0x80bb000c) aIID={4afe423b-43e0-e9d0-82e8-ceb307940dda} aComponent={MediumWrap} aText={Medium 'D:\Virtual Machines\mercury\mercury.vdi' cannot be closed because it is still attached to 1 virtual machines}, preserve=false aResultDetail=0
00:00:06.880525 main     ERROR [COM]: aRC=VBOX_E_OBJECT_IN_USE (0x80bb000c) aIID={4afe423b-43e0-e9d0-82e8-ceb307940dda} aComponent={MediumWrap} aText={Medium 'D:\Virtual Machines\venus\venus.vdi' cannot be closed because it is still attached to 1 virtual machines}, preserve=false aResultDetail=0
00:00:06.880525 main     ERROR [COM]: aRC=VBOX_E_OBJECT_IN_USE (0x80bb000c) aIID={4afe423b-43e0-e9d0-82e8-ceb307940dda} aComponent={MediumWrap} aText={Medium 'D:\Virtual Machines\earth\earth.vdi' cannot be closed because it is still attached to 1 virtual machines}, preserve=false aResultDetail=0
00:00:06.884061 Watcher  ERROR [COM]: aRC=E_ACCESSDENIED (0x80070005) aIID={0169423f-46b4-cde9-91af-1e9d5b6cd945} aComponent={VirtualBoxWrap} aText={The object is not ready}, preserve=false aResultDetail=0

The error messages gave me the idea that it might be a permission problem but

• When I run my CMD.exe prompt, I run it as administrator
• When I try to start the VirtualBox GUI, I also tried it 'as administrator'

Platform information:

Operating System : Windows 10 Pro, Build 10586.17 64-Bit
VirtualBox OSE   : VirtualBox-5.0.10-104061-Win.exe

Any help would be appreciated!

As it turns out the solution is to (in this order):

1. Uninstall the existing installation of VirtualBox and then
2. Do a fresh install of VirtualBox

As per user 'rambound' above:

"Uninstall process unregistered the used COM libraries, install process registered them, feel free provide a detailed answer yourself."