Windows automount and unmount USB drive

I've had success with Sysinternals Process Explorer. With this, you can search to find what process(es) have a file open, and you can use it to close the handle(s) if you want. Of course, it is safer to close the whole process. Exercise caution and judgement.

To find a specific file, use the menu option Find->Find Handle or DLL... Type in part of the path to the file. The list of processes will appear below.

If you prefer command line, Sysinternals suite includes command line tool Handle, that lists open handles.

Examples

• c:\Program Files\SysinternalsSuite>handle.exe |findstr /i "e:\" (finds all files opened from drive e:\"
• c:\Program Files\SysinternalsSuite>handle.exe |findstr /i "file-or-path-in-question"

Update: Microsoft has created the Windows 7 USB/DVD Download tool to make this very easy.

I used this guide as a set of directions - http://kurtsh.spaces.live.com/blog/cns!DA410C7F7E038D!1665.entry

1. Get a USB Thumbdrive between 4-32GB.

If the drive is larger than 32GB, Windows cannot format it as FAT32, so an alternate utility must be used. Windows can still read FAT32 partitions larger than 32GB, though some devices cannot.

2. Run cmd.exe as administrator and enter the following commands followed by Enter

1. diskpart
2. list disk
3. select disk # (where # is your USB drive as determined from step 2)
4. clean (This step will delete all data on your flash drive!)
5. create partition primary
6. active
7. format fs=fat32 quick
8. assign
9. list volume
10. exit
11. bootsect.exe /nt60 F: /mbr (where F: is the drive letter of your USB drive as reported by list volume)

3. Copy the Windows files from the ISO or other source using robocopy

robocopy.exe E:\ F:\ /MIR

where E:\ is the source and F:\ is the destination. Drag-and-drop or copy/paste can also be used, if you know what you're doing.

Configure your PC to boot from the USB drive

In some machines the USB thumbdrive will appear to the BIOS as any other hard drive. You need to muck with the boot sequence to place the thumbdrive higher in the boot order than the local hard drive.

Note that after you do this you might want to reset the boot order in order to ensure that BitLocker doesn't detect boot changes based on the fact that the thumdrive is missing if it was there when you encrypted your drive.