Você pode usar EjectUSB .
Synopsis: EjectUSB is a free tool (just 286 KB) for quickly closing apps running from a USB drive and ejecting the drive from safe removal. It will automatically close all programs running from the drive EjectUSB was run from (host drive), close any explorer windows open to the host drive, remove Windows MUI and MRU entries and recent document shortcuts related to the host drive, and attempt to eject the host drive when done. It can also interface with various utilities to aid in drive ejection.
License: Freeware/Open Source
System Requirements: Win98 / WinME / WinNT / Win2K / WinXP / Vista / Win7