I try to set registry. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\IDE\HardDiskDrive\SerialNumber\Device Parameters\Disk UserWriteCacheSetting works fine. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USBSTOR\USBDiskDrive\SerialNumber\Device Parameters\Disk But UserWriteCacheSetting has no effect. I tested the following way. * I Plug USB Memory. * Copy files to USB * I eject it. * I Reconect it. * I check the files. but write cache in Win2k can be disabled with the "UserWriteCacheSetting" registry entry set to 0. I have UserWriteCacheSetting enabled for the primary IDE hard drive (a western digital 30gb HD) but disabled for my USB card reader and Sony Microvault USB Flash drive. MS KB article 326919 shows how to turn off write caching on a usb 2.0 hard drive. however instead of using the following registry key: "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\IDE\HardDiskDrive\SerialNumber\Device Parameters\Disk" use this one instead for USB storage drives: "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USBSTOR\USBDiskDrive\SerialNumber\Device Parameters\Disk" as in my last post, from the Device Parameters key, create a key called Disk, and then from "Disk", create a registry entry called UserWriteCacheSetting as a DWORD type and set its value to 0.