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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?

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The purpose behind a unique ID for every computer is to identify it in a network. If you have 10 computers it does not matter you can find the culprit easily. Try the same thing with 10,000 computers plus a network of virtual computers and necessity of uniqueness will make is self clear. When you have network centralized software such as some virus scanners will use this to identify which PC is infected. Even if the hacker changes the IP and/or computer name the UUID will be the same. A smart system admin will also have an automatic system in place that if the UUID were changed the computer would be cut off from the network until the reason for this change has been determined.

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Can UUID be changed? or it will always be same until user changed it manually. On what conditions a UUID can be change? – Muhammad Saqib Jan 5 '15 at 11:10
@SaqibSabir If you use sysprep it changes it, and apparently the original question asker has a powershell script to change it. However, unless you are cloning one pc to many, there little if any need to change it. There is a very obscure chance that you could get a duplicate UUID on networks with 10,000 or more but it is almost unheard of. – cybernard Jan 10 '15 at 18:34

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