How can I retrieve a disk's serial number?

Whenever a disk is formatted, the operating system writes a serial number onto it. This number is not guaranteed to be unique, but as it is a 32 bit integer it is unlikely to find a duplicate! The number is often used as part of a copy protection system. This tip shows you how to retrieve the number.

Declarations

Copy this code into the declarations section of the project.

Private Declare Function GetVolumeInformation Lib _
"kernel32.dll" Alias "GetVolumeInformationA" (ByVal _
lpRootPathName As String, ByVal lpVolumeNameBuffer As _
String, ByVal nVolumeNameSize As Integer, _
lpVolumeSerialNumber As Long, lpMaximumComponentLength _
As Long, lpFileSystemFlags As Long, ByVal _
lpFileSystemNameBuffer As String, ByVal _
nFileSystemNameSize As Long) As Long

Code

Function GetSerialNumber(strDrive As String) As Long
    Dim SerialNum As Long
    Dim Res As Long
    Dim Temp1 As String
    Dim Temp2 As String
    Temp1 = String$(255, Chr$(0))
    Temp2 = String$(255, Chr$(0))
    Res = GetVolumeInformation(strDrive, Temp1, _
    Len(Temp1), SerialNum, 0, 0, Temp2, Len(Temp2))
    GetSerialNumber = SerialNum
End Function

Use

An example of using the above function:

Call MsgBox GetSerialNumber("C:")

This will bring up a message box with the serial number of the C drive.