Backing Up and Restoring the Windows Registry

It is always wise to back up your registry before making any changes to it.
This applies, especially, to the novice or to anyone who isn't certain of the effects the changes being made will have on the operating system.
One little mistake with reg editing can take down Windows to the point of not being able to boot.  Backing up the registry before editing makes any errors you make repairable and thus registry editing becomes safe, rather than risky.

There are several ways to backup the registry. However in this article, I will focus on the auto and manual methods built into Windows.

Windows 95
 
Auto Backup

The Windows 95 registry is made up of two files, SYSTEM.DAT and USER.DAT , located in your Windows folder. These registry files are backed up automatically after every successful start of Windows. The backed up files are named SYSTEM.DA0 and USER.DA0 and are also located in your Windows directory.  Should Windows fail to start due to a registry error, you will be prompted to restart your computer to restore your registry. During the reboot, the backed up da0 files are used to restore your registry to the previous state it was before the error. This method, however, is by no means fail proof.
It is quite common to end up with corrupted dat and da0 files. This can easily happen when restarting after a bad regedit.  Therefore, it is wise to manually back up the registry before making any system changes.

Windows 95 also contains an additional system.dat backup file called System.1st located in your root drive(usually c:) This represents your registry as it was when you first installed Windows. If your registry becomes so corrupted that you can not recover it, you can always try replacing c:\windows\system.dat with c:\system.1st and  then renaming system1st, system.dat. In my experience, however, this rarely works and it's usually easier to just do a reinstall. The reason is that System1st is very bare bones; it doesn't include all the many programs you may have installed after installing Windows.

 

 

In WIndows 95, manually backing up the Regisry is a simple matter of copying system.dat and user.dat and saving them to a safe location(personally, I back up my registry files to a Windows folder named Reg)
Note, that by default, dat files are hidden, so you must have Show All Files enabled to find these files.  To do that:
In any folder, click View>Options>View and then check Show All Files.

 

Restoring

Should the registry become corrupt, you can use your backed up files to restore it.  To that, you would restart your computer in native DOS and at the C:\> prompt, type the following commands, pressing Enter after each one(in this example, it is assumed your backed up reg files are in C:\Windows\Reg)

attrib -h -s -r c:\windows\system.dat
attrib -h -s -r c:\windows\user.dat
attrib -h -s -r c:\windows\regbak\*.dat
copy c:\windows\regbak\system.dat c:\windows\system.dat /v /y
copy c:\windows\regbak\user.dat c:\windows\user.dat /v /y

Once the files are copied, reboot.

 

Scanreg in Windows 95

 

Scanreg from Windows 98\98se can also be used to back up\ restore the registry in Windows 95.  Simply copy the 98 files, scanregw.exe and scanreg.exe to your 95 hardrive. Both are self executing files.  Double click scanregw.exe and your registry will be scanned and then you will be given the option to back it up.

Windows 98\98se

Registry Checker - Auto Backup & Restore

The Registry Checker(aka ScanReg) is a built-in Registry backup and restore tool and comes in two versions -  scanregw.exe whiich runs only in Windows and  scanreg.exe which runs only.
 
 
SCANREGW.EXE
 
The WIndows Registry checker(scanregw.exe) scans your Windows 98 Registry for errors once a day. If there are no errors, the Registry Checker automatically backs up the Registry. If an error is found, the Registry Checker automatically restores the most recent copy of the Registry. The Registry Checker keeps, by default, five backup copies of the Registry and stores them as .CAB files in C:\Windows\Sysbckup. The first backup is called RB000.CAB, the second RB001.CAB and so on.  You can increase the number of backups created by editing scanreg.ini and changing the MaxBackupCopies entry.

 
SCANREG

To back up your registry in DOS using scanreg, restart your computer in Dos mode and at the DOS prompt type:
scanreg /backup 

and press Enter.  Scanreg will back up your registry and then return a DOS prompt.

 

Restoring

In most cases, you will be restoring the Registry in DOS mode using scanreg.exe.
Start Windows in native Dos mode - the easy way to do this is to simply choose Restart in MS-Dos Mode from the Shutdown menu or if you can't get into Windows, reboot. press F8 at the startup screen and then choose Command Prompt Only from the 98 Boot Menu.
At the prompt, type scanreg / restore and follow the prompts.
You'll see a box  listing each backup, the date each was created, as well as information that tells you whether the backup has been used to successfully start the operating system. All you need to do is select a backup and press Enter.
To see all your scanreg options, type scanreg /? at the DOS prompt.
 
 
Manual Backup & Restore
 
You can also use the Registry Checker to  backup the registry whenever you choose.  Click Start>Run and type in scanregw.exe to start the Registry Checker. After scanning the Registry for errors, you will be asked if you would like to make another backup of the Registry.  Click Yes.

 
As well you can manually backup the 98 Registry by copying system.dat and user.dat which are in your Windows folder, to a safe place(same way as in Windows 95)  This is actually the easiest way to backup the registry.
It's just a matter of copying and pasting the two files to a new folder.
Note that these files are hidden by default.  If  you can't find them, open any folder and click View>Folder Options>View tab and choose Show All Files.

To restore the registry from your own backed up system.dat and user.dat, follow the instructions presented for Windows 95.

 
Automating the Manual Backup & Restore of the Win9x Registry

The  entire manual backup and restore of the Windows 95\98\98se Registry can be simplified with a couple of bat files that when clicked will automatically backup or restore your Registry.  Clickhere for full instructions.

Windows 2000
 
Backup

Windows 2000 has the Windows 2000 Backup utility for backing up the Registry. It's located in the the System Tools menu. When you start it, you'll see an item called System State, under My Computer. The System State is a collection of system specific data and as you will see includes the Registry.
Simply select Registry and click the Start Backup button.

Another method of backing up the Registry in Windows 2000 is by rebooting your system and when you see the Please Select the Operating System to Start message, press F8 and then use arrow keys to select the Last Known Good Configuration option and press Enter. This instantly restores the most recent copy of the Registry.
You can also use this method in Windows NT.


Restore

To restore the Win2K Registry, start the Backup utility, select the Restore tab, choose the backup media, and then select the System State check box. Note that this not only restores the Registry, but all of the System State data.


Windows Me

Scanreg is also part of Windows Me but the main restore feature of Me is
System Restore which automatically monitors and records changes made to the essential Windows system files including the registry.
If your system becomes corrupt, System Restore allows you to undo (or "roll back") a change that caused instability in your system
To use, Click Start>Programs>Accessories>System Tools, and then click System Restore.
Click Restore my computer to an earlier time and click Next.
In the calendar that appears choose which Restore Point to roll your system back to and click Next.  You will then be prompted to close all programs and reboot. On restart, a confirmation screen appears. Click OK to continue using your computer.
The next time you start System Restore, you will see a third option, Undo my last restoration. This is available in the event that the Restore Point you rolled back to does not correct the original problem that you were having and so you can easily get back to the point in time that you started troubleshooting.
For more info on System Restore:
http://support.microsoft.com/support/kb/articles/q267/9/51.ASP