9

I was installing some software and it said that the locking criteria is the system UUID. Now I know what UUID stands for. I know they are unique and are 128 bits long. I know how to generate them from a windows power shell. But my question is what is the system UUID on a windows 7 machine. Where is it stored. And what is the purpose behind having a UUID for every computer? Could someone please clear these doubts for me? What are they used for apart from verifying that the same software is not installed again on the same computer?

Sab
  • 627
  • 4
  • 8
  • 16
  • Hm, there are multiple IDs here. First of all every Windows machine has a machine security identifier (SID) and if it is domain joined it gets a domain-sid as well. To change the first one the system must be rebooted with the sysprep tool, the second one changes when you register the machine in the domain. Both are not real UUIDs (but unique IDs). There is a hardware machine UUID (in fact I think multiple), there is the network card MACs, there are filesystem and disk IDs and many more.. – eckes Jun 07 '17 at 19:56
  • The UUID in the mainboard is used I think for windows activation as well (`wmic csproduct get UUID`). Not beeing able to change them is to make spoofing harder, to reduce accidents and because some stuff depends on it. It is not clear which UUID is the one you care about. However if you are entitled to move the software then your vendor should tell you how, dont crack it. – eckes Jun 07 '17 at 19:56

1 Answers1

4

System UUID cannot be changed : it depends upon the hardware. It is determined at creation time by the hypervisor : KVM, Hyper-V, VMWare, ...

You can get the UUID this way :

On Windows

cmd.exe

wmic csproduct get UUID

Powershell

Get-WmiObject -Class "Win32_ComputerSystemProduct" | Select-Object -Property UUID

On Linux based Systems

#! /bin/sh
dmidecode -s system-uuid
Daryn
  • 473
  • 5
  • 9
MUY Belgium
  • 353
  • 1
  • 4
  • 17
  • It should be noted that both commands need to be executed with supervisor privileges. – zx485 Mar 18 '19 at 22:27
  • I have a problem with my KVM, UUID on windows are not identical... – MUY Belgium Sep 20 '19 at 08:34
  • *"System UUID cannot be changed"* - Not true. Programs like [Ghost](https://www.symantec.com/products/ghost-solutions-suite), which is used to clone workstations from a master image, change the UUID for each newly installed image. If the UUID was not changed, then a workstation would encounter obscure errors when trying to join the domain. – jww Sep 22 '19 at 05:37
  • @jww Does it change the _system UUID_ (which can be read out of the motherboard's firmware by Linux via dmidecode)? That seems out of scope of a disk clone operation, no matter how OS-aware. – JamesTheAwesomeDude Sep 14 '22 at 15:47
  • @jww Programs like ghost creates a copy of the DMI system UUID. Consequently, it is a new machine and a new UUID is created. – MUY Belgium Sep 19 '22 at 12:31