In part, this hotfix is designed to improve the performance of the default shadow copy driver (Volsnap.sys) when there are high input/output levels. The hotfix also includes a larger initial size for the shadow copy storage area: 300 MB instead of 100 MB.

This issue occurs because of a race condition in the Volume Shadow Copy Service driver (Volsnap.sys). When the volume size is being changed in the snapshot creation process, the race condition might be encountered.

Fixes an issue that generates a "0x0000007E" Stop error.

This issue occurs because of a race condition in the Volume Shadow Copy driver (Volsnap.sys). This race condition may occur when the volume size changes during the snapshot creation process.

Fixes an issue in which the cluster service takes longer than expected to bring a CSV volume online in Windows Server 2012 R2. This issue occurs when logs of VSS snapshots are accumulated by the Volsnap provider.

To apply this hotfix, you must be running Windows Server 2008 R2. To use the hotfix, you do not have to change the registry. You do not have to restart the computer after you apply this hotfix. This hotfix does not replace a previously released hotfix.

Each restore point creates a snapshot of Windows that Volsnap.sys must validate during the startup process. When you create many restore points, the boot plan for the ReadyBoot feature eventually exceeds the size limit of 512 KB, and cannot be stored.

Consider the following scenario: You create a transportable VSS snapshot on a Windows Server 2008-based computer that has Active Directory-related roles installed. The VSS_VOLSNAP_ATTR_AUTORECOVER flag is not enabled. In this scenario, VSS snapshot creation may fail.

On a computer that is running Windows Server 2008 or Windows Vista, you create a copy-on-write snapshot for a volume. On the volume that stores the copy-on-write snapshot, some other snapshots are deleted. In this scenario, the copy-on-write snapshot may become corrupted. A supported hotfix is available from Microsoft.

Fixes an issue in which Windows Server 2008 systems that host Hyper-V virtual machines restart unexpectedly, and you receive a Stop error 0x0000007E when you back up the virtual machines by using the Hyper-V writer.