How to find USB drive letter?

Question

I'm writing a setup program to install an application to a USB drive. The application is meant to be used only from USB drives, so it would save an extra step for the user by automatically selecting USB drive to install to.

I might explore using Nullsoft or MSI for install, but since I'm mostly familiar with .NET I initially plan to try either custom .NET installer or setup component on .NET.

Is it possible to determine the drive letter of a USB flash drive on Windows using .NET? How?

Solution 1

You could use:

from driveInfo in DriveInfo.GetDrives()
where driveInfo.DriveType == DriveType.Removable && driveInfo.IsReady
select driveInfo.RootDirectory.FullName

Solution 2

C# 2.0 version of Kent's code (from the top of my head, not tested):

IList<String> fullNames = new List<String>();
foreach (DriveInfo driveInfo in DriveInfo.GetDrives()) {
    if (driveInfo.DriveType == DriveType.Removable) {
        fullNames.Add(driveInfo.RootDirectory.FullName);
    }
}

Solution 3

This will enumerate all the drives on the system without LINQ but still using WMI:

// browse all USB WMI physical disks

foreach(ManagementObject drive in new ManagementObjectSearcher(
    "select * from Win32_DiskDrive where InterfaceType='USB'").Get())
{
    // associate physical disks with partitions

    foreach(ManagementObject partition in new ManagementObjectSearcher(
        "ASSOCIATORS OF {Win32_DiskDrive.DeviceID='" + drive["DeviceID"]
          + "'} WHERE AssocClass = 
                Win32_DiskDriveToDiskPartition").Get())
    {
        Console.WriteLine("Partition=" + partition["Name"]);

        // associate partitions with logical disks (drive letter volumes)

        foreach(ManagementObject disk in new ManagementObjectSearcher(
            "ASSOCIATORS OF {Win32_DiskPartition.DeviceID='"
              + partition["DeviceID"]
              + "'} WHERE AssocClass =
                Win32_LogicalDiskToPartition").Get())
        {
            Console.WriteLine("Disk=" + disk["Name"]);
        }
    }

    // this may display nothing if the physical disk

    // does not have a hardware serial number

    Console.WriteLine("Serial="
     + new ManagementObject("Win32_PhysicalMedia.Tag='"
     + drive["DeviceID"] + "'")["SerialNumber"]);
}

Source

Comments

[MSalters]

Also gets FireWire drives, but mthat ight actually be the right thing to do though.

[Ivan Ičin]

But doesn't return USB hard drives, I think it is a problem.

[Wouter]

ManagementObject, ManagementObjectSearcher and ManagementObjectCollection (implicitly retrieved with .Get()) have a Dispose method that should be called.

[Florian Straub]

I used your solution to find the drive letter of one single flash drive of which I knew the serial number. It worked well under Windows 10 but in Windows 7 the serial number was empty. I figured out that the serial number is also part of drive["PNPDeviceID"] which I now test if it contains the serial number I was looking for. Thanks!

[EricSchaefer]

A USB hard drive is not exactly a "USB flash drive", or is it? ;-)