The Alcor USB Storage Windows driver is typically a driver associated with USB flash drives or other USB storage devices that use a controller chip made by Alcor Micro. Alcor Micro is a company that designs and manufactures semiconductor solutions for USB flash drives, card readers, and similar devices.
The driver allows Windows to communicate with and manage the USB storage devices based on Alcor's controller. When you plug in a USB drive with an Alcor controller, the system may require the specific Alcor driver to ensure proper functionality, such as read/write access and other device-specific features.