Microsoft

Windows 98's System File Checker utility

Windows 98 offers a helpful utility for scanning and repairing corrupted system files on your workstation. Paul Suiter explains how to use the System File Checker utility.


You’re constantly adding and removing programs from your Windows system. Most users don’t realize how many new drivers and executables go along with the addition of a new program. There also may be some changes in files that are shared by other programs. It can cause quite a disruption when other programs attempt to use the file and it doesn’t act in the intended way. And you may wonder if Windows actually deletes programs that you uninstall. Many programs leave files behind after you’ve uninstalled them. When you uninstall a program, you may even see a message asking if you really want to delete a certain file because other programs share it. If you used to dread adding or removing programs, relax! Now, there is help: the Windows 98 feature called System File Checker.

Accessing System File Checker
System File Checker offers Windows 98 users an easy way of scanning and correcting corrupted system files. It also can help you find files that have been modified or even deleted. Since Windows-based applications occasionally share files, users need to be able to track files that may be replaced by the installation of a new application. System File Checker will track these changes and, if necessary, even restore the file from the original disk or CABs.

To access the System File Checker utility, begin by selecting Start | Programs | Accessories | System Tools | System Information. From the Tools menu, select System File Checker. An even quicker way to bring up the utility is to click Start | Run, and type sfc.exe.

Once you’ve opened the System File Checker window, you’ll be given two options: Scan For Altered Files (the default) or Extract One File From Installation Disk.

Scan for altered files
When you want to scan the files, leave the default choice selected and click OK. The System File Checker utility will compare the system files against a baseline of file information contained in a file called Default.sfc. This file is part of your original Windows 98 installation. The System File Checker utility looks for corrupted files by comparing the checksum of the system files to the checksum of the baseline files. The checksum is a specific number that’s derived from summing all of the ones and zeros that make up the file. If the sum of the system file doesn’t match the number for the file in the baseline but all other parameters are correct (file date, version, and so forth.), System File Checker considers the file to be corrupted. When this situation occurs, the utility displays the filename and suggests that you restore the file.

When System File Checker finds that the other verifying information (version, file date, and so forth) has changed, it considers the file to be modified. The utility then gives you three options: Update Verification Information, Restore File, or Ignore. If you choose to update the verification information, the file information within Default.sfc will be modified to reflect the new attributes of the file. Of course, you should choose this option only if you are absolutely positive that the file is correct. If you decide to restore a file, you’ll need to choose the source from which the file that you’re using as the restore file is located and choose the path for where you want it placed. If you want to ignore a file, you do just that—ignore it. But the file will pop up again the next time that you run System File Checker.

At the end of each system check, System File Checker lets you view the details of the check. It displays the number of files and folders that were checked, along with the number of updates that were made to the verification file. Needless to say, I was astonished to find this area populated when there were no interruptions of the process to let me know that it had found a file that was not registered. I concluded that, if you’re updating your system with Windows updates, the updates aren’t considered to be changes that must be pointed out.

Extract one file from installation disk
When you need to restore a file, select the Extract One File From Installation Disk option. In the File Name text box, type the name of the file that you want to extract. If you aren’t sure of the name, use the Browse button to search the system’s folders for the filename. In some cases, there may be files that aren’t part of the CAB files and can’t be extracted. Some files, such as Control.ini and Msbatch.inf, are created at the time of the install and aren’t part of the CAB files.

You also can change several settings in System File Checker. Begin by clicking the Settings button, which is located at the lower right-hand corner of the main window where you started the process. In addition to the Settings tab, you will see the Search Criteria and the Advanced tabs.

The Settings tab offers several options for backing up files before you restore another file in their place. The first option is to back up the file before restoring. If you select this option, the System File Checker utility will always make a copy of the file before a restore is performed. The second option will prompt you to back up the file or bypass the backup process before you restore the file. The third option tells the utility to skip the backup process when you’re restoring. You also can change the default path for storing the copies of the files that are backed up. The default path is set to store the backup files in the Sysbckup folder under the Windows directory.

The next set of options deals with the log file that’s created by the utility each time that it’s used. The two options give the user a choice of appending the log or overwriting the log file during each search. You also can view the log by clicking the View Log button, which opens the log in Notepad or, if the log is too big, in Wordpad. The log has the same information that you’d see if you clicked the Details button in the window that’s displayed at the end of each search. The log also contains information on any files that were updated, added, or restored.

The two check boxes at the bottom of the Settings tab are used to include additional parameters for the search. If you select the boxes, System File Checker will search for changed and/or deleted files. If the search finds files that fall under either of these categories, you’ll see a prompt.

The Search Criteria tab enables you to add file types and folders to the search. When you add other folders or extension types, they may be outside of the scope of the baseline. When that happens, you may be prompted to update, restore, or ignore all of the files that have been added by choosing a new folder or file extension. If you choose to add all of the files to the baseline, make sure that they’re all working properly. If one is already corrupted, the information is saved in the baseline as being corrupted. This problem will place you and System File Checker at a disadvantage.

On the Advanced tab, you can create a baseline file, switch to another baseline file, or restore the default settings of the original file that the utility will use in its file search. To switch to another file for the program’s use, simply type the path for the new file. If you’re unsure of the path, you can use the Browse button. The file that you choose will be used only for that search, and the Default.sfc file will be restored as the baseline once the current operation is complete and you’ve exited System File Checker. When you want to create a new file, click the Create button and choose the name of the file and the location where you want the file to be kept. This file path will appear automatically in the file path box. Return to the Search Criteria tab and select the folders that you want to have searched and the extensions of the files that will be searched.

After you’ve completed all of these steps, click Apply. All of your folder and file extension choices will be saved and associated with the SFC file that you created. At this point, click OK to start the search process.

Conclusion
Keeping your file system in check while using Windows 95 was quite a challenge. Windows 98 simplifies this process with System File Checker. This utility not only scans for corrupted files but also scans for files that have been deleted or modified. You can modify and even create your own baseline for comparing files. With this kind of flexibility, Microsoft makes a leap forward for integrated system maintenance.

Paul Suiter received his first taste of the deadline rush as a photographer for the Montgomery Advertiser, where he earned four photography awards. After receiving degrees in economics and business management from Auburn University, Paul entered the college book business. After managing two bookstores for three years, Paul became a business analyst for EDS. Four years later, Paul continues with EDS, taking its equipment apart, while working with G3 switches and advanced imaging programs. But he’s finally getting back to one of his favorite pastimes—writing. (Of course, he also enjoys spending time with his wife and son.)

The authors and editors have taken care in preparation of the content contained herein, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.

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