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Checking and repairing a disk containing damaged files

3380  Troubleshooting

In the course of using a computer, the disk on which the operating system is stored can become corrupted, either as a result of a crash, a power failure or because software has inadvertently saved information by modifying files that should not have been affected.

A disk contains a catalog in which each saved file is listed with, among other information, its name and location on the disk. If this catalog is corrupted, software that writes files to the disk does so on the basis of unreliable information, and could inadvertently modify and damage legitimate files.

Accessing a partially or totally modified file can lead to an application or even the whole computer crashing. That's why it's a good idea to ensure that the disk catalog and the disk itself are not damaged.

Utility programs are available to perform this check and repair if necessary:

Windows Mac

Run the command prompt (CMD) as administrator and enter the following command:

chkdsk /r c:

The c: drive (usually the internal disk on which Windows is installed) will be tested.

The program informs you that the c: disk cannot be checked, as it is currently in use, and suggests that you check the disk the next time you start up. Accept the suggestion and restart your PC. Start-up will take longer than usual because of the disk check.

At the end of the operation, a message will be displayed if insurmountable problems have been detected. In this case, contact an IT specialist to resolve the problem.

An undamaged catalog does not mean that Windows system files are not damaged. You can check this with another utility program described here.

Start the Disk Utility program, located in the Applications folder, Utilities subfolder. On the left, select the disk you wish to check, then click on the S.O.S. function. Follow the on-screen instructions.

At the end of the operation, a message is displayed indicating whether any problems remain. If so, contact an IT specialist to resolve the problem.

 
Checking and repairing a disk containing damaged files