Event ID 12143 — Storage Initialization

Applies To: Windows Server 2008

This is preliminary documentation and subject to change.

This aspect refers events relevant to the storage of the virtual machine that are caused by storage configuration.

Event Details

Product: Windows Operating System
ID: 12143
Source: Microsoft-Windows-Hyper-V-SynthStor
Version: 6.0
Message: Virtual disk '%3' failed to open because a problem occurred when attempting to open a virtual disk in the chain of differencing disks, '%6': '%4'


Check differencing disk chain

Check the .VHD files in the chain of differencing disks and make sure that all of them exist, are valid images and have the right permissions.

A differencing disk can have another differencing disk as a "parent" disk. It is then said to be "chained".  When you create a chain of differencing disks, it is particularly important to lock all disks except the most recent "child" disk. Any changes made to any older disks would invalidate all later disks in the chain. However, the most recent child disk must be writable so that it can be used by a virtual machine. If a parent disk of a differencing disk cannot be found, for example, if only one of the virtual hard disks is moved, an error will be logged to the Virtual Server event log when you start the virtual machine.

Although virtual server supported creating a differencing disk at the virtual hard disk level, System Center Virtual Machine Manager allows creation of differencing disks only at the virtual machine level. The chain of differencing disks and their relationships is called a "checkpoint" in System Center Virtual Machine Manager.

In Hyper-V checkpoints are called "snapshots".  A snapshot in Hyper-V is a file-based snapshot of the state, disk data, and configuration of a virtual machine at a specific point in time. For more information about snapshots, see http://go.microsoft.com/fwlink/?LinkId=147648.

By default snapshots are stored at %systemdrive%\ProgramData\Microsoft\Windows\Hyper-V\Snapshots.


The virtual machine with the storage attached is able to launch successfully.

Storage Initialization