Loooooong numbers

What are these long numbers? Is there a name for them. How do they arise?
Are they random?

When looking at Share Permissions for example, sometimes a user's ID or
resource does not resolve to a common name, I am left looking at a very long
sequence of numbers. Kinda like the code behind a username. Any information
on this would be greatly appreciated.

Bob

This usually happens when it is a user or group on domain that is not
available. The number is a GUID (Globally unique identifier), or a SID
(Sorry don't know the full one for this). Each user needs to have a
serial number, or value that is totally unique. So again, you are
probably seeing these because the domain controller they belong to no
longer exists, or you have deleted the user and it cannot match the SID
to a name.

Steve

Windows Admin Tools
http://www.intelliadmin.com