Recovered files won’t open? Why they’re corrupt and what to do

You ran recovery software, or managed to copy files off a failing drive, and the folders look full. Then you open them: photos are half grey, documents are full of symbols, videos will not play and thousands of files have names like file0001.jpg. This is a common situation, and the reasons behind it matter, because some of them can still be fixed and some cannot.

What corrupt recovered files look like

• Photos where the top part is fine and the rest is grey, striped or colour-shifted.
• JPEGs that show a thumbnail but give an error when opened.
• Word or Excel files that report “unreadable content” or open as blank pages.
• ZIP files with CRC errors, and PDFs that will not open.
• Videos with no sound, a duration of 0:00, or that freeze part-way through.
• Files with the right type but no original names or folder structure.

Why it happens

The space has been overwritten

When a file is deleted or a drive is formatted, its space is marked as free. Anything written afterwards, including installing recovery software onto the same drive or saving recovered files back to it, can land on top of the old data. Software can still find the file’s entry and give you something with the right name and size, but the contents are now partly someone else’s data. Overwritten data cannot be recovered by anyone.

The files were fragmented

Large files are often stored in several pieces across a drive. If the file system records are damaged, software falls back on “carving”: it looks for the start of a known file type and reads forward. That works for small photos stored in one piece, but for fragmented files it joins the start of one file to the middle of something else. Carving is also why names and folders are lost.

The drive had bad sectors

If the source drive is failing, ordinary software may skip unreadable areas or fill them with zeros and carry on. The copy finishes, but every file that touched a bad area is damaged. Running repeated scans on a drive in this state can make it fail completely.

The data was encrypted

Data read from a BitLocker or FileVault volume without unlocking it, or files encrypted by ransomware, will look like random noise. A file that shows a ransomware extension or a ransom note in the folder is not corrupted in the normal sense, and repair tools will not help.

The SSD has erased it

On many internal SSDs, deleted blocks are cleared by the drive itself soon after deletion (a feature called TRIM). Recovery software then finds file entries that point to empty space, giving files full of zeros.

What to do now

• Stop using the original drive or card. Do not write anything else to it, and do not save recovered files back onto it.
• Keep the original. Do not format it or throw it away because the first attempt gave bad results.
• Do not keep re-scanning a failing drive. If it clicks, slows to a crawl or disconnects during scans, power it off.
• Check a few files properly. Try them in a second program, and use the “Open and Repair” option in Word or Excel for documents. Many cameras embed a small preview inside each JPEG, which can sometimes be extracted if the main image is damaged.
• Look for other copies. Old phones, email attachments, cloud accounts and messaging apps often hold copies of the photos that matter most.

How a lab approaches it

A professional recovery starts by making a full sector-by-sector image of the drive using hardware that can reread weak areas carefully, rather than giving up on them. Work is then done on that image, so the original is not stressed further. Where the file system can be rebuilt, files come back with their real names, folders and correct fragments, which carving software cannot do. If the drive needs physical repair first, such as replacement heads, that is done before imaging.

It is worth being clear about the limits. If the data has been overwritten or erased by TRIM, it is gone. A free assessment will tell you which situation you are in before you spend anything. You can read more about our external hard drive, flash and memory card recovery service.

Get a free assessment

If your recovered files are corrupt and the originals matter, call Data Retrieval on 020 7064 4996 for a free assessment with no obligation, or request a quote online.