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What steps can be taken when a file becomes corrupted or inaccessible? What about human failure, where you've put files into the trash and emptied it, only to realize you've made a terrible mistake? The first thing to remember is simple: don't panic. Unless smoke is emitting from the machine (and sometimes even if it is), it's probably possible to recover at least some data from the system. The worst possible step is the one most users seem to take first: repeated attempts to access corrupted data, possibly including multiple reboots and attempts to re-open the files in question. In many cases, this will only make things worse since you're trying to access potentially damaged sectors on disk; this could cause the OS to overwrite sectors containing the very data you're after. Reformatting the drive is much worse, since it destroys any and all remaining data. If one, or only a few files are involved, you can probably recover them using a commercial data recovery package, such as Recover My Files - they offer a free scan. The thing to remember is that deleted files aren't physically removed from the system; instead, their entries are erased from the disk's internal file listing and their sectors marked as available for use by other files. This is also why you shouldn't just delete files and empty the trash when selling or giving away an older PC! If you run a recovery utility immediately, you're likely to be able to recover entire files. The longer you wait, the more likely it is that the system has started overwriting sectors previously used by your data. This is also why a utility such as the built-in Windows Disk Defragmenter is a bad choice for situations involving accidental file deletions or inaccessible (i.e. invisible to the user) files: if the files' sectors have been released to the OS, the Defragmentation process almost ensures they'll be overwritten and lost. Windows includes another utility known as Scandisk, which is a disk repair and error-checking facility that's accessible by opening My Computer, highlighting a drive, right clicking, then selecting Properties->Tools. The "Check drive for errors" button activates Scandisk, which usually requires a reboot since all files on the disk should be closed when it's executing. This utility can sometimes repair corrupted files, or at least may restore sectors that became inaccessible due to internal disk or filesystem errors. However, it's unlikely to be able to recognize these sectors as part of a specific file type, so you could just end up with useless bits of data that can't be read by your application. Your mileage may vary. If specific file types are involved (Word or Excel documents, for instance), they may be recoverable using utilities such as those offered by Data Recovery. You can download it here. Such utilities can recognize the type of files involved, based on known characteristics of those files, and will attempt to reconstruct a usable file from detached sectors or corrupted data. If an entire disk containing critical data is involved, or a hardware failure has occurred, then it's probably best to turn the disk over to a commercial data recovery company. Such companies can scan entire drives, even those that have failed mechanically. There's no guarantee any of the above will work in a given case, but it's often worth making the attempt before giving up on what may be a large and critical amount of data. |
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