System File Checker

One of the biggest troubleshooting problems in previous versions of Windows was the inability to verify the integrity of the operating system's files. Their integrity could be damaged from several causes: bad sectors on the disk, an incorrect copy from the original CD-ROM during installation, or by being overwritten by subsequently-installed applications. Corrupted system files can play havoc on a system, resulting in application or operating system crashes, or erratic behavior that is difficult to pin down. Now, with Windows 98's System File Checker, you can easily scan all of the Windows 98 files to ensure that they haven't become corrupted or replaced by incorrect versions.

Generally, you can simply click the Start button to start the scan of files. System File Checker compares the CRC values and version numbers of the installed Windows 98 files with a database of expected values. When it finds a problem, a dialog box appears asking you what action it should take with the file in question.

When System File Checker finds a questionable file, you can generally choose from among the following actions:

• Update Verification Information This updates the Windows 98 file database with the new version information and CRC values for the file. Selecting this means that the next time you run System File Checker the file will not be identified as being questionable
• Restore File This causes the file to be restored from the Windows 98 installation point (CD-ROM or network share)
• Ignore Ignores the warning on the selected file. You will be prompted about the file the next time you run System File Checker
• Update Verification Information for All Changed Files The current file and all subsequent changed files will have their information updated in the verification database. There is generally no reason to choose this option unless you are building a new verification database

Before running System File Checker, you can adjust its various options. From the main window, click the Settings button to open the dialog box.

On the Settings tab you can choose how flagged files are backed up; you can always back them up to a directory before restoring different versions from the installation media, you can be prompted on a case-by-case basis for whether they should be backed up, or you can choose to never back them up. You can also change the location to which the files will be backed up before System File Checker restores them. Also on the Settings tab you can control how the System File Checker log is maintained, and you can view the log file from previous uses of System File Checker. Finally, you can direct whether System File Checker looks for changed or deleted files with the appropriate checkboxes. The Search Criteria tab defines which directories will be checked by System File Checker. If you are creating a new verification database, you can define which directories will be tracked, and may included application directories if needed using this tab. You can also define which file extensions will be checked.

The final tab, Advanced, lets you choose which verification database will be used by System File Checker, and also lets you create a new database. Should you require, you can also select the original verification database installed with Windows 98 by clicking the Restore Defaults button.

When installing Windows 98 workstations into an organization, it makes sense to run System File Checker as a final step (after all applications and services have been installed and configured) and create a new verification database, using the Search Criteria tab to select all the directories which contain files that make up the default system configuration. This gives you two benefits that can help future troubleshooting efforts: it gives you a baseline from which to measure changes to the system, and it also monitors application files and settings to ensure that they do not become damaged. After creating the database with the Advanced tab and selecting all the appropriate file types and directories with the Search Criteria tab, run System File Checker and choose Update Verification Information for All Changed files at the first prompted file.