Every file on your machine is a piece of electronic data, and depending on the type of the file in question, will have a certain structure. If the file is written incorrectly, then the data can become scrambled, resulting in a corrupted file.
A corrupted file might display incorrectly, or it might not open or function at all. Files typically become corrupted during the saving process, for example if the power is cut while a write operation is in progress. Bad sectors can also result in a corrupted file, as can viruses or malware. Some operating systems include tools to recover or repair corrupted files, like the System File Checker tool in Windows or Disk Utility in macOS. Many pieces of software – notably Microsoft Office – have a built-in tool to repair corrupted files. You can also find third-party commercial file repair tools, like Stellar File Repair Toolkit, that may be able to help.
Often, even though 99% of the file is intact, the 1% that is corrupted can render it completely useless. As well as occurring during a loss of power, a corrupted file can be caused by a glitch in a program at the wrong time, causing the saving process to halt. So how can you protect yourself against corrupted files, and what should you do if a file you need becomes corrupted? Your first port of call should be consulting your last backup, but this can sometimes prevent problems. If your backup strategy includes automatic syncing – a common feature of many cloud-based backup packages – opening a backed-up version of the file will be fruitless, as it will be a copy of the corrupt file. If your files are synced automatically, make sure you have the option to recall a past version of a file in case the current one becomes corrupted. Corrupted system files might be fixable using System File Checker on Windows or Disk Utility on Mac. It may also be possible to restore from a system restore point before the file became corrupted. Some apps autosave multiple copies of a file, allowing you to roll back if a later version becomes corrupted.
Although OS file repair tools and third-party software can help with corrupted files, they will frequently be unable to help, and it might be best to delete the corrupted file and start again. Obviously, this depends on the nature of the file in question; a corrupt Word document could be anything from a job application to a thesis. A corrupt program file may be obtainable from the developer, and a corrupt photo might be backed up. It’s a good time to mention again the importance of having an up-to-date backup of your data for situations involving corrupted files. Run anti-virus scans on a regular basis, and using a surge protector can prevent problems during the saving process.
