Windows 95/98

Windows Support Menu


Windows 9X Registry

Windows Registry Checker


From a Technical Support point of view, this is the best tool in Windows 98. The Registry Checker is a system-maintenance program that finds and fixes registry problems. Each time you start your computer, Registry Checker automatically scans the registry for inconsistent data structures.

Registry Checker backs up the registry each day. If it finds a serious problem in the registry, Registry Checker will restore the registry from a backup copy. Registry Checker maintains up to five compressed backups of the registry which have successfully started the computer. Registry Checker will fix the registry if a backup cannot be found.

Scanrreg.exe and ScanRegW.exe
File location - ScanReg.exe \windows\command
File location - ScanRegW.exe \windows
Inf file associated? No
Ini file associated? Yes - \windows
How to launch - MSInfo or.. Start - Run - ScanReg[W]

Protect-Mode and Real-Mode Registry Checking


This is the Windows-based protected-mode program. This program scans and then backs up the following system configuration files: Registry (User.dat and System.dat), Win.ini and System.ini. This scan occurs automatically when the system is started. You can run ScanRegW.exe when you want to force a scan and backup these files.

If ScanRegW detects a problem with the registry, it offers to restart the computer to fix the problem. An error message on boot suggests that you run the real-mode ScanReg to "fix" the registry, by either restoring from a backup or if no backups are available it repairs the current registry.


This is the MS-DOS-based real-mode program. This program scans the system configuration files early in the boot process. ScanReg can also fix bad registry files. If errors are found, the program warns you and prompts you to start Scanreg /Restore to restore a known good copy of these files.

Once bad files are backed up, ScanReg provides a list of known good Cab files and indicates whether the system configuration files stored in the Cab have been used to start Windows 98 successfully. (ScanReg Cab files are discussed later in this lesson.) You should choose the Cab file that was most recently used to start Windows 98, unless you are certain that a specific Cab file will successfully start Windows 98, for example, a Cab file that you created by backing up the system files manually.

Tip: ScanReg does not remove keys left by a poorly designed uninstall. ScanRegW does not detect, as a problem, the same problems that ASD detects. ScanRegW detects corruption to the internal structure of the registry files, it does not look at the content of the keys. ASD searches specific strings for the binary value 01.

The following table identifies the differences between ScanRegW and ScanReg.

Real or Protected mode? Protected-mode Real-mode
Run at Setup? No Yes, but in protected mode.
Scan Registry? Yes Yes
Compresses backup Yes No
Restore registry No Yes
Runs automatically Yes, every time computer is started Yes, if a registry problem is detected.
Fix Registry? No Yes
Backup Registry? Yes Yes

ScanRegW has the ability to run in Safe Mode since it scans the registry on the disk, not in memory.

ScanReg Command-line Options

The following table identifies the command-line options for ScanReg.

Command Line Option
/FIX Repairs registry instead of restoring from a backup.
/BACKUP Forces a backup of current system.
/RESTORE Forces a rollback (overrides /BACKUP switch)
/AUTOSCAN For ScanRegW. Scans registry and does not display a dialog box.
/AUTORUN Silently scans, if there is a problem automatically restores a good registry and tells the user there was a problem that has been fixed.
/COMMENT="comment" Adds the specified comment to the CAB file while backing up.


Both ScanRegW and ScanReg use settings from the ScanReg.ini file. The following table lists those settings.

Keyname and Default Value
Other Values
Backup=1 Run ScanReg at startup and make a backup automatically. 0. Scanreg is not run at startup.
Optimize=1 Removes up to 500k of blank space in registry. Automatic optimization is skipped if set to 0
ScanregVersion=0.0001 ScanReg.ini version number Not applicable.
MaxBackupCopies=5 Number of backups to store in the backup folder. 0 to 99.
BackupDirectory= Backup directory where the cabs are stored. It must be a full path. Example c:\tmp\backup Defaults to windir\sysbckup by default.
Files=[dir code,] file1,file2,file3 Additional system files to backup into the cab file. Filenames are separated by ','. The dir code can be: 10: windir (ex. c:\windows) 11: system dir (ex. c:\windows\system) 30: boot dir (ex. c:\) 31: boot host dir (ex. c:\) None.

Note: If Scanreg cannot create a backup in the location specified by the Backup folder in the SCANREG.INI file, it defaults to placing the CAB file in the %WINDIR% folder.