Online Help

How to configure Windows MachineId fallback

This page explains how to use the Non-unique Windows BIOS UUIDs setting on Admin Center > Site Settings > Settings > Inventory settings.

Use this setting when Windows devices report duplicate, placeholder, or otherwise non-unique BIOS UUID values and AlloyScan starts matching more than one device to the same identity.

AlloyScan normally uses the BIOS UUID as a stable identity signal for Windows devices. Some hardware vendors and virtualization platforms can return duplicate or placeholder UUID values instead, which can make different devices look like the same asset. In practice, that can lead to overwritten audit history, unstable identity matching, or multiple rows that appear to belong to one device.

Common problematic values include:

  • 00000000-0000-0000-0000-000000000000
  • FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF

If different devices seem to overwrite each other's audit data, or the Inventory shows the same asset identity for more than one host, check whether the affected devices report the same Audit ID value in their Audit tab.

Scope

This setting is per-Site. A list created in one Site is not available in another Site.

Admin Center > Site Settings > Settings > Inventory settings

What this setting does

The Non-unique Windows BIOS UUIDs list lets you mark specific BIOS UUID values as non-unique.

For listed values, AlloyScan uses Windows MachineId instead of the BIOS UUID for device identity. The same fallback behavior can also apply to empty UUIDs when Treat empty UUIDs as non-unique is enabled.

When to use it

Use the list when:

  • multiple devices report the same BIOS UUID
  • a BIOS UUID is a placeholder or otherwise clearly not unique
  • cloned or reimaged Windows devices keep colliding on BIOS UUID
  • you want AlloyScan to stop matching those devices by the reported BIOS UUID

How to maintain the list

  1. Open Admin Center.
  2. Go to Settings > Inventory settings.
  3. Under Non-unique Windows BIOS UUIDs, add each problematic BIOS UUID value and press Enter.
  4. If some devices report empty BIOS UUID values, select Treat empty UUIDs as non-unique.
  5. Save the settings.

What to copy from Inventory

Copy the UUID value shown as Audit ID on the device's Audit tab in Inventory and add it to the list.

Limitations

Windows MachineId is generated by Windows, not by device firmware. It can change after:

  • Windows reinstallation
  • a major Windows upgrade
  • system reset
  • reimaging
  • sysprep
  • some virtual machine cloning operations

If MachineId changes on a device, AlloyScan may create a duplicate inventory record. If that happens, locate the duplicate and delete it manually.

Because of that, MachineId is best used only for known problematic BIOS UUID values.