What are corrupted files?
Corrupted files are files that have become unusable, inaccessible, or unreadable due to data errors. These errors can occur for a variety of reasons, such as power outages, hardware malfunctions, software bugs, viruses, or human error. Some common signs of a corrupted file include inability to open the file, error messages when trying to open it, strange characters or text, missing data, and more. Corrupted files can affect any file type like documents, spreadsheets, photos, videos, etc. Dealing with them can be frustrating, but there are some steps you can try to recover or fix corrupted files.
What causes file corruption?
There are various potential causes of file corruption:
- Sudden power outage or improper system shutdown: If a computer shuts down unexpectedly while a file is still open or being modified, the data may not get fully written to the storage device resulting in a corrupted file.
- Faulty hardware: Issues with storage devices like hard drives or memory RAM chips can introduce errors in data storage/retrieval leading to corruption.
- Software crashes or glitches: Bugs, viruses, or conflicts in software programs may interrupt file operations and cause corruption.
- Storage device failure: Problems with drives, disk read/write heads etc. can make data unreadable.
- Sync errors: File transfer interruptions during copying, moving or syncing files between devices can corrupt files.
- Human errors: Accidental deletion, edits or overwrites can alter file data and lead to corruption.
So in summary, both hardware and software related issues can introduce errors in file data that prevents them from being opened or accessed normally. Backing up regularly helps protect against data loss from corruption.
What are the common signs of a corrupted file?
Here are some tell-tale signs that indicate a file is corrupted:
- Error messages: Applications show error messages like “File is corrupted and cannot be opened” when you try opening the file.
- Unable to open: The file refuses to open and the application crashes or freezes when trying to load it.
- Incorrect file size: The file size differs drastically from what is expected for that file type.
- Partial data: Only some parts of the file’s data can be accessed and the rest is missing.
- Strange text/characters: The file content displays random characters, garbled text and other strangeness.
- Data loss: Parts of the file’s data is just missing when opened.
- Hanging/freezing: The program hangs or freezes indefinitely while trying to open the corrupted file.
If you notice any of these issues when trying to open or access a file, chances are high that it has become corrupted. The next steps would be trying to recover its contents or repair the file if possible.
How to try to repair and recover corrupted files
When faced with a corrupted file, there are some repair and recovery steps you can try to salvage and regain access to its contents again. Here are some things to attempt:
Use built-in repair tools
Many programs include built-in repair utilities that can fix common file corruption errors. For example, Microsoft Office has an Inbox Repair tool that can be used to recover damaged Outlook data files. Similarly, disk utilities can scan drives and repair corrupt sectors. Run the appropriate repair tool for the file type that is damaged.
Open file in recovery mode
Some applications like Microsoft Word allow you to open documents in recovery mode, which ignores errors and attempts to recover file contents as much as possible. Parts of the data may still be accessible through this method.
Use file recovery software
Specialized file recovery tools are available that can scan storage media and reconstruct corrupt files by merging recovered fragments. Examples include Recuva, TestDisk, and EaseUS Data Recovery Wizard. This option works best for minor corruption, but advanced tools may recover data even from heavily damaged files.
Restore from backup
If the file corruption is severe, the most reliable method is to restore the affected file from a recent backup that contains the intact undamaged version. Cloud services and external drives make it easy to maintain backups and quickly replace corrupted files.
Recover previous versions
Microsoft Windows has a File Version History feature that tracks changes and allows restoring older versions of files if needed. You may be able to roll back to an earlier working copy before the corruption happened.
Manual file repair
As a last resort, users can attempt to manually repair certain file types using a Hex editor tool to analyze and modify the raw file data. This method requires technical expertise but may work in cases where all automated repair attempts have failed. Backup the file before attempting manual edits.
Recreate file content
For irrecoverable/overwritten files, the only option may be to recreate the content from scratch if possible, or seek professional data recovery help as a paid service if the file is valuable enough. Preventing regular file backups is key to avoid this worst-case scenario.
Best practices to avoid and prevent file corruption
While file corruption cannot always be avoided entirely, following some best practices can greatly reduce the chances of occurrence and minimize potential damage:
Maintain backups
Keep regular backups of important files in external locations like cloud storage or external drives. This provides the ability to easily replace corrupted files from a known good copy.
Handle storage media correctly
Follow correct procedures for disconnecting external USB drives to avoid damage. Also avoid exposing drives to magnets, moisture, excessive heat etc. to prevent errors.
Check drive health
Perform regular disk error scans and check SMART drive health metrics to catch issues early before severe failure and corruption happens. Replace aging drives.
Close files/programs properly
Always use proper shutdown/restart procedures and close open files before disconnecting or powering off devices to prevent potential file write issues.
Update software
Keep all applications and drivers updated to the latest stable versions. Updates fix bugs and vulnerabilities that could lead to crashes and file corruption.
Use antivirus tools
Run reputable antivirus and anti-malware tools to detect and block viruses, spyware and other malicious programs that may delete or corrupt files.
Handle portable media carefully
Avoid improperly removing portable drives like USB flash drives or SD cards while files are still being written or read from them to prevent corruption.
Use file optimization tools
Regularly optimize and repair Office files, databases, disk drives and other data sources to detect and fix errors before they escalate into corruption issues.
Limit drive fragmentation
Defragment storage devices occasionally to minimize fragmentation, which can increase risk of data errors and corruption over time.
When to seek professional file recovery services
In cases of catastrophic drive failure or severe file system corruption that make a drive completely inaccessible, elaborate professional data recovery techniques may be necessary to attempt extracting files. This requires expensive specialized equipment and technical expertise. A few scenarios where professional help should be considered:
- Mechanical or physical hard drive failure – for example, disk read/write head crash.
- SSD failure leading to inaccessible NAND flash storage chips.
- Severe virus/malware infection that encrypts or fully deletes files.
- Accidental repartitioning or reformatting of a drive.
- Fire/flood damage to storage media.
- Avoiding data loss from a damaged device with irreplaceable files.
Professional recovery can cost hundreds to thousands of dollars with no guarantee of success, so the value of recovered data should outweigh the payment. But for business critical file recovery it may be a wise investment.
Questions to ask before choosing a file recovery service
If professional recovery is deemed necessary, research and vet providers carefully before handing over a damaged device. Some questions to ask:
- What types of media and failures do they have experience recovering from?
- What are their data recovery capabilities and technology?
- What is their success rate and can they provide past customer reviews/testimonials?
- Do they have a cleanroom facility for hard drive recovery?
- What is the exact diagnostic and recovery process and timeframe?
- Are free quotes provided without obligation to pay if unsuccessful?
- What are all the costs involved for the recovery service?
- Will they keep your storage device and data totally secure?
Avoid companies that ask for upfront payment without assessing the actual recoverability of files first. Choosing an experienced professional provider known for high success rates is crucial for the best chance of file recovery.
How to recover specific file types
The techniques for recovering corrupted files may vary based on the file type and format. Here are some tips for common file formats:
Documents (Word, Excel, PDFs etc.)
Use the Open and Repair utility in Microsoft Office applications. Also try opening in Office Compatibility Mode or a different version of Office. PDF files can be repaired online using free tools. Restore from backups or autosaved versions if available.
Media files (photos, videos, audio)
Try repair tools built into media editing programs like Photoshop. Use free corrupted photo/video repair software programs. FFmpeg can fix some corrupted videos. Recover from file fragments using data recovery tools.
Archive files (ZIP, RAR etc.)
Archive software like WinRAR often include repair utilities to extract contents from damaged ZIP or RAR files by reconstructing their structure. Free ZIP repair tools are also available.
Database files
Most database management systems like SQL Server, MySQL, Oracle etc. include corruption repair and recovery commands to rebuild damaged database files from redo logs. Consult a database admin.
Outlook PST files
Run Microsoft Inbox Repair tool (SCANPST.EXE) to check and restore corrupted PST files. Third-party PST repair tools are also available with added capabilities. Import recovered data into new PST.
Virtual machine files
Restore damaged VM files like VMDK/VHD disks from snapshots or backups. Use VM repair tools provided in virtualization platforms like VMware and VirtualBox. Seek expert help.
Table summarizing main methods of corrupted file recovery
| Recovery Method | When to Use | Effectiveness |
|---|---|---|
| File repair tools | Minor corruption, fixes errors | Very effective for minor issues |
| File recovery software | Reconstructs files from fragments | Works if large sections recoverable |
| Restore from backup | Severe corruption with backup available | 100% recovery if recent backup |
| Previous file versions | To roll back before corruption | Fully restores earlier version |
| Manual file repair | Last resort when all else fails | Unpredictable, needs expertise |
| Professional recovery service | Severe hardware/file system damage | Highest chance for hard cases |
Conclusion
While file corruption can lead to frustrating data losses, there are often ways to salvage and recover corrupted files using built-in repair features, recovery software, backups, and professional help if needed for valuable irreplaceable data. Follow best practices like regular backups, stable hardware, and safely ejecting drives to reduce likelihood of corruption happening in the first place. Acting quickly after corruption occurs gives the best shot for successful file recovery with minimal or no data loss.
