ComputerCharacteristics includes every physical Drive

[schland]

WindowsComputerCharacteristics uses SerialNumber, Win32_PhysicalMedia from all physical medias attached to computer.
This leads to the issue that if you connect external usb hard drive the generated hardware id changes.

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To avoid the issue where connecting an external USB hard drive changes the generated hardware ID, you need to refine the selection of hardware characteristics to those that are less likely to change. Typically, you would want to use identifiers that are intrinsic to the system and not affected by removable devices.

Here’s an updated version of your WindowsComputerCharacteristics class, where it uses more stable hardware characteristics like Win32_Processor and Win32_BIOS only. This should mitigate the problem caused by external USB devices:

#if NET6_0_OR_GREATER
    [SupportedOSPlatform("windows")]
#endif
    internal class WindowsComputerCharacteristics : IComputerCharacteristics
    {
        public IEnumerable<string> GetCharacteristicsForCurrentComputer()
        {
            yield return GetValue("ProcessorID", "Win32_Processor");
            yield return GetValue("SerialNumber", "Win32_BIOS");
            yield return GetValue("Product", "Win32_BaseBoard");
            // Removed Win32_PhysicalMedia to avoid issues with external USB drives
        }

        private static string GetValue(string property, string type)
        {
            var sb = new StringBuilder();
            try
            {
                var searcher = new ManagementObjectSearcher($"select {property} from {type}");
                foreach (var share in searcher.Get())
                {
                    foreach (PropertyData pc in share.Properties)
                    {
                        if (pc.Name == property && pc.Value != null)
                        {
                            sb.Append(pc.Value.ToString());
                            break;
                        }
                    }
                }
            }
            catch
            {
                sb.Append(property).Append(type);
            }
            return sb.ToString();
        }
    }
}

Key Changes:
Removed Win32_PhysicalMedia: This is to ensure that the generated hardware ID does not change when an external USB drive is connected or disconnected.
Added Win32_BaseBoard.Product: This property is usually stable and tied to the motherboard, providing a consistent identifier.
Explanation:
Win32_Processor.ProcessorID: A unique identifier for the processor, stable across reboots and hardware changes.
Win32_BIOS.SerialNumber: A unique identifier for the BIOS, which remains consistent unless the BIOS itself is replaced.
Win32_BaseBoard.Product: The product identifier of the baseboard (motherboard), which is consistent and less likely to change.
This approach leverages more stable hardware characteristics to generate a unique hardware ID, thereby minimizing the risk of the ID changing with removable devices. If further stability is needed, you can investigate other Win32 classes and properties that are tied to non-removable components.