Great! It works fine with my drive now, too.

Standalone. I just trigger the function with: Eject ( "F:" ).
Many thanks for looking into it.

But yes, it is blank.
It looks like the following condition is not met:

If ( NumGet( STORAGE_DEVICE_NUMBER, "UInt" ) = FILE_DEVICE_DISK )

If I omit the above if clause then sPHDRV = \\\\.\\PHYSICALDRIVE0

DeviceType: 7
DeviceNumber: 2
PartitionNumber: 1
---------------------------

hVol = 248 sPHDRV = (blank) ErrorLevel = -2 The drive in question is: ---------------------------------------------- Caption: Seagate Expansion USB Device Description: Disk drive DeviceID: \\.\PHYSICALDRIVE1 InterfaceType: USB MediaLoaded: -1 MediaType: External hard disk media Model: Seagate Expans...

Thank you. Unfortunately, I can't make it work.
Can you suggest how to debug?

Great. Thank you so much.

I get this message: --------------------------- Eject.ahk --------------------------- Error at line 19. Line Text: Local sHex, Split, sDID, nDID := 0, nVT := 1, nTC := A_TickCount, VAR, nLen := VarSetCapacity( VAR,1... Error: Local variables must not be declared in this function. The program will ex...

Hex is:

B14CB7010000100000000000

yes, ErrorLevel is -3

Here's the content of Msgbox:

---------------------------
Eject.ahk
---------------------------
\\
---------------------------
OK
---------------------------

I get A_LastError = 1.
I'm trying to safely remove a portable USB drive (2.5 inch, 1TB).
It works clicking the standard Win 7 tray icon ('Safely Remove Hardware').
Any suggestion?