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What is a Corrupted File?

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By: Jessica

June 24, 2018

two people using a computerAt some point or another, every computer user has tried opening up a file on his device only to see a message that says “The file you are trying to access is unavailable or has been corrupted.” This may understandably alarm some users, as a “corrupted file” sounds like one that has taken on a life of its own and has “gone rogue,” spreading some kind of evil disease throughout a computer. Not only does a “corrupted file” sound like something that is a sign of damage or a major problem on a device, but in some cases, file corruption is the result of some kind of malware that has invaded the computer. However, although the presence of corrupted files can be an indication of an issue requiring immediate attention, in many cases, the cause of a corrupted file can be the cause of something harmless, trivial, or temporary;  with a few simple steps, the file can be restored and accessible again. Here are some typical causes of file corruption, what you can do if it happens, and measures you can take to prevent it from happening in the future.

Corrupted Files

A corrupted file is a computer file that fails to operate properly, rendering it inaccessible and unusable. When a user tries to open a corrupted file, a dialog box with an error message usually pops up saying something like “The application was not able to open ‘mydocument.pdf’ because it is either not a supported file type or because it has been damaged.” File corruption happens somewhere in the electronic writing process that creates or saves a version of a file on a disk or storage medium. Computer files are pieces of electronic data, so depending on the types of files they are, e.g., word processing document or audio file, they will each have a specific type of structure designed to store certain types of data. If the wrong type of data is written to a file, the data is stored in an incompatible or incorrect area of the file, or if the writing process is interrupted and leaves the data incomplete, then corruption of that file may result. File corruption can happen not only to application files used in programs like Adobe Photoshop or Microsoft Word, but also to system or program files that actually enable a program or operating system (OS) to function.Sometimes, an application will detect an error during the file saving process and display an error message that prompts the user to try saving the file again. In other cases, however, there may be no notification message, and a user won’t learn that a file has been corrupted until he tries to open it sometime afterwards. There are a variety of factors that can impact the writing of a file to a disk or medium and lead to corruption.

Common Causes of File Corruption

  • Hard Disk or Storage Media Problems – One possible cause of file corruption is if there are errors in a computer’s hard disk or problems with the storage medium to which the corrupted file is saved, even if the file saving process gets completed. Corruption of operating system or program files that run an application can be caused by errors or bad sectors on a hard disk. Storage media like flash drives and compact discs can also have bad sectors or experience damage that lead to improper writing of a file to the medium and subsequent file corruption. Other tools and applications like compression programs that reduce file sizes can also have problems that corrupt a file while it’s being compressed or otherwise modified. An Internet browser that is downloading a file in an email attachment, for instance, may have some spontaneous glitches that cause it to improperly decode the attachment or fail to adequately write it to the device’s disk.
  • Application Performance Lag - If an application freezes up or becomes unresponsive during the process of saving a file, then the file may not be saved properly and could become corrupted. Application crashes and freeze ups may happen when too many other programs are being used on a computer at the same time. Closing some applications or increasing the RAM on a device may help cut down on such an issue.
  • Power Loss/Computer Crashes – A sudden loss of power during file saving or a computer crash can be a culprit behind file corruption. The application files themselves and also the operating system files that enable an OS to perform can become corrupted during an abrupt power loss or crash.
  • Software Bugs/Temporary Quirks – In many situations, the corruption of a computer file can be due to a random fluke like a temporary glitch in the operating system that goes away sometime later. In other cases, the software application in which the file is being saved may have some bugs or code defects that need to be corrected. Although software updates sent out by the software manufacturer are meant to fix software bugs, sometimes the updates themselves have faulty code that can cause file corruption and other issues out of nowhere.
  • Malicious Software – As malware like computer viruses and Trojan horses are designed to steal information, modify programs and data, and even commandeer devices, one of their potential effects or objectives is often to corrupt and acquire copies of the files on a computer.

What to Do in the Event of File Corruption

  • Use Another Device – One straightforward way to determine if either a file is corrupted or if it is the application or device that is causing problems is to try opening the file on another device. If the file is successfully opened on a different device, then it’s the application or device that has an issue, which could be major or minor like file corruption in the functional files. If it’s determined that a particular program or operating system is the reason for file problems, then reinstallation of that application or of the device’s operating system may be necessary.
  • Operating System Tools – If the file corruption is the result of a random operating system error, then using the computer’s operating system tools can usually fix the problem and get performance back to normal. These system tools include a suite of features, such as device managers, system configuration and diagnostic tools, memory diagnostic tools that check RAM for errors, and hard drive scanners that detect and fix system errors that can cause crashes. These tools can also check for bad sectors on hard drives and attempt to recover files stored on them.
  • Salvage and Repair – Fortunately, there are both free and paid recovery applications available on the Web that can repair or at least save portions of a corrupted file, depending on the severity. One such program is Recuva by Piriform. Available in a basic free version and paid professional versions, Recuva can restore files lost from a crash as well as those resulting from damaged drives. These applications, however, cannot guarantee file restoration, depending on the root cause of the corruption.
  • Delete and Replace – If recovery tools or the system tools of a computer’s operating system cannot save and revive a corrupted file, then the last resort is to simply delete the corrupted file and replace it with a backup copy or the last saved version of the file. If the corrupted file was sent from a source or downloaded from a website, you can just ask the sender to send the file again or try downloading the file once more. Many applications like Microsoft Word have built-in capabilities that allow users to save and restore previous versions of a file in the event of a program crash or file corruption.
  • Undo Bad Updates - In some cases, the manufacturers for a particular software application will send out regular updates to users for them to download and update their applications. This is especially important, since many of these updates include fixes for any security vulnerabilities or performance function issues. However, sometimes these updates themselves can have flaws in their code that lead to file corruption during operation of the program. If the software update is the guilty entity behind the file corruption, then uninstall the update and contact the software provider so they can send a corrected update and offer some assistance.

File Corruption Prevention

  1. Surge Suppressor or UPS - To prevent sudden interruptions in your computer’s power supply, protect it with a surge suppressor or an uninterruptible power supply (UPS). A UPS, in particular, can prevent not only file corruption resulting from abrupt power losses but also from hardware issues that can come with improper power shutdowns.
  2. Right Power Off– Always turn off your computer properly by selecting the shutdown option through the interface. This can help ensure that any open applications are closed properly and don’t have any technical mishaps that can lead to file corruption.
  3. Antivirus Protection – Keep your devices safe with antivirus software that can help guard against viruses or other malware that can corrupt computer files.
  4. Backups – Regularly maintain about two to three copies of file backups, keeping them on separate storage media like USB flash drives or online in cloud storage. For data storage applications like Dropbox and Google Drive, check to see if you have the option of saving various versions of the same file.
  5. Application and Recovery Discs – Keep operating system recovery discs that came with your computer as well as application discs handy in case you need to reinstall your OS or software program if you encounter any major file corruption or performance issues.

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