Editing USB mass storage device class (section)

=== Microsoft Windows ===
Microsoft Windows has supported MSC since Windows 2000. There is no support for USB supplied by Microsoft in Windows before [[Windows 95]] and [[Windows NT 4.0]]. [[Windows 95]] OSR2.1, an update to the operating system, featured limited support for USB. During that time, no generic USB mass-storage driver was produced by Microsoft (including for [[Windows 98]]), and a device-specific driver was needed for each type of USB storage device. Third-party, freeware drivers became available for Windows 98 and Windows 98SE, and third-party drivers are also available for Windows NT 4.0. [[Windows 2000]] has support (via a generic driver) for standard USB mass-storage devices; [[Windows Me]] and all later Windows versions also include support.

[[Windows Mobile]] supports accessing most USB mass-storage devices formatted with [[File Allocation Table|FAT]] on devices with USB Host. However, portable devices typically cannot provide enough power for hard-drive [[disk enclosure]]s (a {{convert|2.5|in|adj=on}} hard drive typically requires the maximum 2.5&nbsp;[[Watt|W]] in the USB specification) without a self-powered [[USB hub]]. A Windows Mobile device cannot display its file system as a mass-storage device unless the device implementer adds that functionality. However, third-party applications add MSC emulation to most WM devices (commercial Softick CardExport and free WM5torage). Only memory cards (not internal-storage memory) can generally be exported, due to file-system issues; see [[#Device access|device access]], below.

The [[AutoRun]] feature of Windows worked on all removable media, allowing USB storage devices to become a portal for [[computer virus]]es. Beginning with [[Windows&nbsp;7]], Microsoft limited AutoRun to CD and DVD drives, updating previous Windows versions.<ref>{{cite web |url=http://blogs.technet.com/msrc/archive/2009/04/28/changes-in-windows-to-meet-changes-in-threat-landscape.aspx |title=Changes in Windows to Meet Changes in Threat Landscape |publisher=TechNet Blogs |date=2009-04-28 |access-date=2012-11-07}}</ref>