In every computer, the registry is saved in separate files in the windows directory. The Windows XP registry files are located in the %systemroot%/system32/config directory where %systemroot% is usually WINDOWS or WINNT. Within the Windows XP registry files are the structure of the hives and corresponding location of each hive. This article will help you understand how the Windows XP registry files correspond with the hierarchial structure.
In the registry, there are hives that correspond to several files. Hives are a collection of keys, subkeys and values that contain the configurations for the operating system and programs. In the registry, there are 5 groups: HKEY_CLASSES_ROOT(HKCR), HKEY_CURRENT_USER(HKCU), HKEY_LOCAL_MACHINE(HKLM), HKEY_USERS(HKU), and HKEY_CURRENT_CONFIG(HKCC).
For the corresponding hives, you will see several types of extensions: no extension, .alt, .log, and .sav.
No Extension: The complete registry hive
.alt: An alternate copy of the registry hive
.log: A log of changes that have occurred within the registry hive
.sav: This is an automatic backup created from when a setup or program installation occurs.
Here are the corresponding files:
HKCC: System, System.alt, System.log, System.sav
HKCU: Ntuser.dat, Ntuser.dat.log
HKLMSAM: Sam, Sam.log, Sam.sav
HKLMSecurity: Security, Security.log, Security.sav
HKLMSoftware: Software, Software.log, Software.sav
HKLMSystem: System, System.alt, System.log, System.sav
HKU.DEFAULT: Default, Default.log, Default.sav
Another thing to mention is that there is a “repair” copy just in case your registry gets corrupted. These files are located in the %systemroot%/repair directory. These usually will come in handy when you get bootup errors and need a find a clean copy of the registry. One way to fix this problem is to use the Windows CD to get into the recovery console. From there, you would be able to copy the registry files from the “repair” folder to the system32/config directory.
So you can see the logic behind the registry editor with the structure and location of the Windows XP registry files. By knowing this information, you can understand how a registry works with the operating system. These files can get corrupted just like any other files and knowing where they are located can help in troubleshooting many issues in the future. The Windows XP registry files are very delicate to work with, so make sure that you are taking absolute care when manipulating these files.