How to Recover f= rom a Corrupted Registry That Prevents Windows XP from Starting=

Th= is article was previously published under Q307545

SUMMARY

Th= is article describes how to recover a Windows XP system that does not start because of corruption in the registry. This procedure does not guarantee fu= ll recovery of the system to a previous state; however, you should be able to recover data when you use this procedure.

You can repair a corrupted registry in Windows XP. Corrupted registry files= can cause a variety of different error messages. Please refer to the Knowledge = Base for articles regarding error messages related to registry issues.

This article assumes that normal recovery methods have failed and access to= the system is not available except by using Recovery Console. If an Automatic System Recovery (ASR) backup exists, it is the preferred method for recover= y; it is recommended that you use the ASR backup before you try the procedure described in this article.

Note Make sure = to replace all five of the registry hives. If you only replace a single hive or two, this can cause potential issues, since software and hardware may have settings in multiple locations in the registry.

If you experience a repetitive occurrence of registry corruption related issues, Microsoft recommends that you obtain and install the hotfix in the following article:

3= 18159 Damaged Registry Repair and Recovery in Windows XP

Th= is update is also included in Windows XP Service Pack 1.

MORE INFORMATION

Wh= en you try to start or restart your Windows XP-based computer, you may receive one= of the following error messages:

Windows XP could not start because the following file is missing or corrupt: \WINDOWS\SYSTEM32\CONFIG\SYSTEM

Windows XP could not start because the following file is missing or corrupt: \WINDOWS\SYSTEM32\CONFIG\SOFTWARE

Stop: c0000218 {Registry File Failure} The registry cannot load the hive (file): \SystemRoot\System32\Config\SOFTWARE or its log or alternate

The procedure described in this article uses Recovery Console, System Restore, = and lists all the required steps in specific order to ensure that the process completes fully. After you complete this procedure, the system should retur= n to a state very close to the system before the problem occurred. If you have e= ver run NTBackup and completed a system state backu= p, you do not have to follow the procedures in parts two and three; you can skip to part four.

Part One=

In= part one, you boot to the Recovery Console, create a temporary folder, back up t= he existing registry files to a new location, delete the registry files at the= ir existing location, and then copy the registry files from the repair folder = to the System32\Config folder. When you are finished with this procedure, a registry is created that you can use to boot back into Windows XP. This registry was created and saved during the initial setup of Windows XP, so a= ny changes and settings that took place after Setup completes are lost.

To complete part one, follow these steps:

1. = Boot to the Recovery Console.

2. = At the Recovery Console command prompt, type the follo= wing lines, pressing ENTER after you type each line:

md<= /span> tmp
copy c:\windows\system32\config\system c:\windows\tmp\system.bak
copy c:\windows\system32\config\software c:\windows\tmp\software.bak
copy c:\windows\system32\config\sam c:\windows\tmp\sam.bak
copy c:\windows\system32\config\security c:\windows\tmp\security.bak
copy c:\windows\system32\config\default c:\windows\tmp\default.bak

delete c:\windows\system32\config\system=
delete c:\windows\system32\config\software
delete c:\windows\system32\config\sam
delete c:\windows\system32\config\security
delete c:\windows\system32\config\default

copy c:\windows\repair\system c:\windows\system= 32\config\system
copy c:\windows\repair\software c:\windows\system32\config\software
copy c:\windows\repair\sam c:\windows\system32\config\sam
copy c:\windows\repair\security c:\windows\system32\config\security
copy c:\windows\repair\default c:\windows\syste= m32\config\default

3. = Type exit to quit Rec= overy Console. Your computer will restart.

Note This procedure assumes that Windows XP is installed to the C:\Windows folder. Make sure to change C:\Windows to the appropriate windows_folder if it is a different location.<= br>
If you have access to another computer, to save time, you can copy the text= in step two, and then create a text file called "Regcopy1.txt" (for example). To create this file, run the following command when you boot into Recovery Console:

batch regcopy1.txt=

Th= e Batch command in Recovery Con= sole allows for all the commands in a text file to be sequentially processed. Wh= en you use the batch command, you do not have to manually type as many command= s.

Part Two=

To complete the procedure described in this section, you must be logged on as = an administrator, or an administrative user (a user who has an account in the Administrators group). If you are using Windows XP Home Edition, you can lo= g on as an administrative user. If you log on as an administrator, you must first start Windows XP Home Edition in Safe mode. To start the Windows XP Home Edition computer in Safe mode, follow these steps.

Note Print these instructions before you continue. You cannot view these instructions after = you restart the computer in Safe Mode. If you use the NTFS file system, also pr= int the instructions from Knowledge Base article Q309531, which is referenced in Step 7.

1. = Click Star= t, click Shut Down= (or click Turn = Off Computer), click Restart, and then click OK (or click Restart).=

2.      =              Press the F8 key.

On a computer that is configured to start to multiple operating systems, you can press F8 when you see the Startup menu.

3.      =              Use the arrow keys to select the appropriate Safe mode option, and then press ENTER.

4.      =              If you have a dual-boot or multiple-boot system, use t= he arrow keys to select the installation that you want to access, and then pre= ss ENTER.

In= part two, you copy the registry files from their backed up location by using Sys= tem Restore. This folder is not available in Recovery Console and is normally n= ot visible during normal usage. Before you start this procedure, you must chan= ge several settings to make the folder visible:

1.      =              Start Windows Explorer.

2.      =              On the Too= ls menu, click Folder options.

3.      =              Click the = View tab.

4.      =              Under Hidd= en files and folders, click to select Show hidden files and folders, and then click to c= lear the Hide protected operating sy= stem files (Recommended) checkbox.

5.      =              Click Yes<= /span> when the dialog box is displayed that confirms that you want to display the= se files.

6.      =              Double-click the drive where you installed Windows XP = to get a list of the folders. If is important to click the correct drive.

7.      =              Open the System Volume Information folder. This folder appears dimmed because it is set as a super-hidden folder.

Note This folder contains one or more _restore {GUID} folders such as "_restore{87BD3667-3246-476B-923F-F86E30B3E7F8}".

Note You may re= ceive the following error message:

C:\System Volume Information is not accessible. Access is denied.

If you get this message, see th= e following Microsoft Knowledge Base article to gain access to this folder and continue with the procedure:

3= 09531 How to Gain Access to the System Volume Information Folder

8.      =              Open a folder that was not created at the current time. You may have to click Details on the View men= u to see when these folders were created. There may be one or more folders start= ing with "RP= x under this folder. These are restore points.

9.      =              Open one of these folders to locate a Snapshot subfold= er; the following path is an example of a folder path to the Snapshot folder: <= o:p>

C:\System Volume Information\_restore= {D86480E3-73EF-47BC-A0EB-A81BE6EE3ED8}\RP1\Snapshot

10.      =          From the Snapshot folder, copy the following files to = the C:\Windows\Tmp folder:

·            = ;            &n= bsp;          _REGISTRY_USER_.DEFAULT

·            = ;            &n= bsp;          _REGISTRY_MACHINE_SECURITY

·            = ;            &n= bsp;          _REGISTRY_MACHINE_SOFTWARE

·            = ;            &n= bsp;          _REGISTRY_MACHINE_SYSTEM

·            = ;            &n= bsp;          _REGISTRY_MACHINE_SAM

11.      =          Rename the files in the C:\Windows\Tmp folder as follo= ws:

·            = ;            &n= bsp;          Rename _REGISTRY_USER_.DEFAULT to DEFAULT <= /span>

·            = ;            &n= bsp;          Rename _REGISTRY_MACHINE_SECURITY to SECURITY

·            = ;            &n= bsp;          Rename _REGISTRY_MACHINE_SOFTWARE to SOFTWARE

·            = ;            &n= bsp;          Rename _REGISTRY_MACHINE_SYSTEM to SYSTEM <= /span>

·            = ;            &n= bsp;          Rename _REGISTRY_MACHINE_SAM to SAM<= /p>
Th= ese files are the backed up registry files from System Restore. Because you used the registry file created by Setup, this registry does not know that these restore points exist and are available. A new folder is created with a new = GUID under System Volume Information and a restore point is created that include= s a copy of the registry files that were copied during part one. This is why it= is important not to use the most current folder, especially if the time stamp = on the folder is the same as the current time.

The current system configuration is not aware of the previous restore point= s. You need a previous copy of the registry from a previous restore point to m= ake the previous restore points available again.

The registry files that were copied to the Tmp = folder in the C:\Windows folder are moved to ensure the files are available under Recovery Console. You need to use these files to replace the registry files currently in the C:\Windows\System32\Config folder. Recovery Console has limited folder access and cannot copy files from the System Volume folder by default.

Note The proced= ure described in this section assumes that you are running your computer with t= he FAT32 file system. For additional information about how to access the System Volume Information Folder with NTFS file system, click the following article number to view the article in the Microsoft Knowledge Base:

309531= How to Gain Access to the System Volume Information Folder

Part Three

In= part three, you delete the existing registry files, and then copy the System Res= tore Registry files to the C:\Windows\System32\Config folder: =

1.      =              Boot to Recovery Console (or by using a Windows 98 Boot Disk).

2.      =              At the command prompt, type the following lines, press= ing ENTER after you type each line:

del c:\windows\system32\config\= sam

del c:\windows\system32\config\security =

del c:\windows\system32\config\software =

del c:\windows\system32\config\default <= br>
del c:\windows\system32\config\system
copy c:\windows\tmp\software c:\windows\system32\config\software

copy c:\windows\tmp\system c:\windows\system32\config\system

copy c:\windows\tmp\sam c:\windows\system32\config\sam

copy c:\windows\tmp\security c:\windows\system32\config\security

copy c:\windows\tmp\default c:\windows\system32\config\default

Note Some of the preceding command lines may be wrapped for readability. <= /p>
3.      =              Type exit to quit Rec= overy Console. Your computer restarts.

Note This procedure assumes that Windows XP is installed to the C:\Windows folder. Make sure to change C:\Windows to the appropriate windows_folder if it is a different location.<= br>
If you have access to another computer, to save time, you can copy the text= in step two, and then create a text file called "Regcopy1.txt" (for example).

Part Four

1.      =              Click Star= t, and then click All Programs.

2.      =              Click Acce= ssories, and then click System Tools.

3.      =              Click Syst= em Restore, and then click Restore to a previous RestorePoint.

REFERENCES

For additional information about using Recovery Console, click the following article numbers to view the articles in the Microsoft Knowledge Base: =

3= 07654 HOW TO: Install and Use the Recovery Console in Windows XP

2= 16417 HOW TO: Install the Windows XP Recovery Console

2= 40831 HOW TO: Copy Files from Recovery Console to Removable Media

3= 14058 Description of the Windows XP Recovery Console

2= 43381 How to Use Recovery Console for Data Recovery

For additional information about System Restore, click the following article numbers to view the articles in the Microsoft Knowledge Base:

3= 06084 HOW TO: Restore the Operating System to a Previous State in Windows XP=

2= 61716 System Restore Removes Files During a Restore Procedure