What causes memory card corruption?
Memory cards can become corrupted for a variety of reasons. Some common causes include:
- Removing the memory card from a camera or device before it has finished writing data
- Using the same memory card in different cameras that are not fully compatible
- Physical damage to the card from drops, bends, water exposure, etc.
- Electrical issues like power outages or static electricity
- Inexplicable software bugs or glitches
Any of these issues can lead to the memory card file system becoming damaged, making it impossible for the operating system to recognize the files on the card. The good news is that even if a card seems totally unreadable, the underlying data is likely still intact and may be recoverable with the right tools and techniques.
Why format vs just deleting content?
When memory card data seems to be corrupted or inaccessible, some people assume they can just delete the existing content and continue using the card. However, this is not recommended.
Deleting the files and reformatting a memory card does NOT reliably erase the underlying data. The only way to completely overwrite a card and make data unrecoverable is to deliberately scrub it using data destruction software.
Instead, you should format the card to repair the file system without overwriting data. This gives data recovery tools the best chance of restoring your files. Deleting files individually makes it harder to recover them intact.
Formatting thoroughly recreates the card’s directory and allocation structures without actually removing your photos, videos, and other content. It maps out usable storage areas in an orderly way so your device can once again save and retrieve data.
How to format a memory card for recovery in Windows?
If you need to recover data from a corrupted memory card, the first step is formatting it properly using a Windows PC:
- Insert the memory card into your card reader or USB port.
- Open File Explorer and right click on the drive letter assigned to the card.
- Select “Format…” from the menu.
- Under File System, choose FAT32 or exFAT format.
- Check the Quick Format box to skip scanning for bad sectors.
- Click Start to begin formatting.
This will format the card without changing the underlying data. Quick formatting is crucial – you do NOT want Windows to scan for bad sectors at this stage. That could overwrite portions of your files before recovery software examines them.
Once formatted, the card should show up as working normally when reinserted in your device. Now you can use data recovery software to attempt extracting the photos, videos, documents, and other content.
How to format a memory card for recovery on Mac?
The process for formatting a corrupted memory card to prepare it for data recovery using a Mac is very similar to Windows:
- Insert the problematic memory card into your Mac’s card reader or USB port.
- Open Disk Utility (located in Applications > Utilities).
- Select the memory card device in the left sidebar.
- Click Erase at the top of the Disk Utility window.
- Choose either MS-DOS (FAT32) or ExFAT format.
- Select Erase to quickly format the drive.
As with Windows, it is important to use the Quick Erase option and NOT run First Aid or deep scanning functions prior to recovery. This avoids overwriting files before recovery software can read them.
After quick formatting on Mac, the memory card should show up as a properly formatted, blank drive. You can now use Mac data recovery software to scan the card and extract your photos, videos, and other content.
How to check if a memory card is corrupted?
There are a few clear signs that point to a corrupted memory card:
- Your camera or device shows error messages when the card is inserted
- Files you just shot or saved are not showing up on the card
- You can’t access, open, copy or edit files on the card
- Strange filenames show up for files that aren’t yours
- Your device asks you to format the card before use
Basically, any unusual behavior when trying to view or access the files on a memory card typically means it is corrupted in some way. The card may appear blank, read-only, or completely unrecognized by your computer.
If you suspect your card is corrupted, do NOT keep shooting photos or saving files to it. Any new data could overwrite portions of your photos and make them harder to recover. Take it out and properly format it before attempting data recovery.
How does data recovery software work?
Data recovery software is able to resurrect files from a corrupted memory card in a few key ways:
- Scans the raw data: It directly scans the raw data on the drive, independent of the file system.
- Looks for file signatures: Searches for distinct signature patterns that denote the start of certain file types – JPEGs, MP4s, DOCs, etc.
- Checks the allocation table: Reads the card’s allocation table to see which sectors are mapped to which files (if the file system is not totally corrupt).
- Extracts preview images: Some advanced software can reconstruct enough of the visual data to show thumbnail previews of recoverable photos.
This enables recovery of files even when the card seems blank or has a corrupted file system. Different software uses different techniques, but all rely on extracting files from raw data – not from the operating system’s file directory.
Does reformatting a memory card affect recovery?
Reformatting a memory card using the quick format option does NOT affect the ability to recover data from it. This is an important step before running data recovery software.
Quick formatting simply recreates the blank file system while leaving all previous data intact. It allows the card to be usable again in your device so the recovery software can interact with it.
A full format that scans for bad blocks could potentially overwrite some data. Fortunately windows and Mac OS now do quick formats by default. Just make sure you don’t check any options like “restore disk to full capacity” during formatting.
As long as you use the quick format option, reformatting will never reduce chances of recovery. The previous files remain fully intact until new data physically overwrites them.
What’s the success rate for memory card data recovery?
The chances of successfully recovering data from a corrupted memory card depends on the severity and cause of the corruption:
- If the photos or files seem to vanish abruptly, recovery has over a 90% success rate.
- Partial physical damage to the card reduces chances to 60-70% on average.
- Severe corruption from failed firmware updates may limit recovery to 30-50%.
- Completely catastrophic physical destruction can make recovery impossible.
In most common corruption scenarios, expect an average recovery rate around 65-75%. Higher capacity cards have lower odds, while smaller cards often see over 80% of files resurrected.
With the right software and techniques, you can optimize your chances. But there’s no guaranteed way to know if critical files can be recovered until attempting it.
Can you recover data after formatting a memory card?
Yes, data recovery is still possible even after formatting a memory card, as long as you avoid overwriting the data.
When you format a card, the file structure is renewed, but all previous files remain in place until replaced with new data. Quick formatting prevents any overwriting.
Data recovery tools ignore the blank file system entirely, scanning the raw data for signatures that match photos, videos, documents, and other file types.
As long as the card has not been filled up with new content after formatting, comprehensive data recovery is achievable in most cases. Just make sure to format the card before attempting recovery.
What are the risks of overwriting data on a corrupted card?
Here are the key risks if you continue shooting photos or saving data to a corrupted memory card:
- New files may overwrite portions of your damaged/lost photos or videos.
- Any chance of recovering old files becomes much lower.
- Formatting or deleting content after corruption makes recovery harder.
- Overwriting critical file system data can make the entire card unrecoverable.
- More files are likely to be fragmented and incomplete if recovered.
Basically, any new data you save to the card after corruption greatly reduces recoverability of the original files. Even device logs or temporary files can begin overwriting important data.
As soon as you suspect corruption, stop using the card immediately to prevent additional overwriting. Then you can format it to prepare the card for recovery software.
Can you recover data from a formatted hard drive?
Hard drives can also be recovered after formatting, as long as the existing data has not been overwritten. The same general principles apply:
- A quick format simply rewrites the file system, leaving your original documents, media, and other files intact.
- Recovery software scans for old files by searching raw data independent of the file system.
- Documents and media are recoverable until physically overwritten with new data.
- Avoid saving anything new to the formatted hard drive to prevent overwriting.
Success rates are generally higher for hard drives than memory cards due to their more robust data storage. As long as a quick format was performed, expect 70-90% of files to be recoverable in most cases.
The longer a drive operates after formatting, the higher chance of involuntary overwriting by temporary files, caches, etc. So recovery should be attempted soon after formatting for optimal results.
How can I avoid needing data recovery in the future?
You can help prevent memory card corruption and data loss with a few simple habits:
- Safely eject cards from devices before removing them.
- Use high quality name brand memory cards rather than cheap generic ones.
- Store cards properly in cases when not in use.
- Minimize exposing cards to moisture, dirt, heat, magnets, or physical damage.
- Back up your photos and videos regularly to another device or cloud storage.
- Upgrade to fresh cards periodically as they do wear out over years of use.
While memory card corruption cannot be avoided 100% of the time, careful handling and backups make it less likely. And leveraging professional data recovery services can get back even your most precious data should the worst still occur.
Conclusion
Formatting a memory card or hard disk drive prepares it for data recovery when files seem to vanish or become corrupted. Using the quick format option prevents overwriting old files while letting you reuse the card or disk again.
Data recovery tools scan below the file system to extract recoverable photos, videos, documents, and other files. As long as new data has not overwritten your original files after corruption or formatting, there is an excellent chance of resurrecting what seems lost.
With the right recovery software and by avoiding saving anything new after corruption, you can restore your important memories and data even from cards or drives that appear totally blank or damaged.