What is the SID of the operating system?

        The SID is a unique identification number. Used to identify the identity of the user. Exists in the local SAM database. This library is not authorized by the administrator to read by default. Only SYSTEM is fully controlled. For example, we can modify the administrator's account. How does the system recognize you before or after the modification? Is it still an administrator? In fact, it is to look at the SID number. So SID never repeats. Even if you reinstall some SID numbers, it is still different. The system after 2000/XP has a higher dependence on SID. Obviously, the registry, NTFS, EFS (encrypted files), etc. all rely on SID. Simple GHOST only copies the SID in the system. The SIDs on the other partitions that may be recorded are not copied. Therefore, recovery may cause access failure. Use SYSPREP to clear the SID number in the system. After this recovery, the system will automatically regenerate. The SAM library can be opened in XP like this: REGEDIT HKEY_LOCAL_MACHINESAMSAM At this point you can't see anything. Give yourself permission by the last method. Right click permission. Give the administrator group FULL CONTROL to see information such as SID. The SID is very long. For example: S-1-5-21-1177238915-1767777339-839522115