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 driver (Volsnap.sys). This race condition may occur when the volume size changes during the snapshot creation process.

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 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.

This issue occurs because the Volume Shadow Copy driver (Volsnap.sys) calculates the boundary of the free disk space that has copy-on-write protection incorrectly.

This issue occurs because the Volsnap.sys driver spends too much time marking available space on the volume when holding a spinlock. This hotfix is also available at Microsoft Update Catalog. A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article.

In this race condition, NTFS uses a target device object that is not a volsnap device object. Therefore, the Flush & Hold Writes operations are not sent to the Volsnap.sys driver.

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.

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.

Provides an update that increases the MinDiffAreaFileSize registry key value limit from 3 GB to 50 GB in Windows 8.1 or Windows Server 2012 R2.