How to Recover Corrupted Files

File recovery has two distinct meanings: recovering a deleted file (data recovery on disk) and repairing a corrupted file whose bytes are still on disk but unreadable. This guide focuses on the latter — files that exist but won't open or open with errors. Office documents, PDFs, photos, and videos all have different corruption modes and different repair tools. Microsoft Office and Apple iWork have surprisingly capable built-in recovery. PDFs often repair via simple re-rendering tricks. Photos and videos are the hardest because they're typically large binary blobs where a single bad sector can break everything downstream. We cover free tools first, only mention paid software when the alternatives fail, and tell you honestly when a file is unrecoverable.

1. 1
   First — verify it's actually corrupted

   Try opening the file on another device or in another app first. A Word doc that won't open in Word may open fine in LibreOffice. A photo that fails in Photos may render in IrfanView. "Corrupted" sometimes just means "the app I tried doesn't like this format variant."
2. 2
   Make a backup before attempting repair

   Copy the corrupted file to a safe location before running any recovery tool. Some repair attempts modify the file in place. If the first attempt fails, you want to start from a clean copy, not a partially mangled one.
3. 3
   Recover Word documents with Open and Repair

   Open Microsoft Word → File → Open → Browse. Select the corrupted .docx. Click the dropdown arrow next to the Open button and choose Open and Repair. Word attempts to fix structural issues. If that fails, try opening the file in Google Docs (free) — its parser is more permissive.
4. 4
   Recover Excel spreadsheets

   In Excel, use the same Open and Repair dialog as Word. If repair fails, try opening the .xlsx as a ZIP archive (rename .xlsx to .zip and extract). The XML files inside often contain the data even when the wrapper is corrupted. Free tool SheetJS can also extract data from broken xlsx files.
5. 5
   Recover PowerPoint presentations

   Open and Repair works for .pptx. Alternatively, rename the .pptx to .zip and extract — the slide XML files and embedded media survive even if the file won't open. You can rebuild a working pptx by re-zipping the contents.
6. 6
   Recover PDFs that won't open

   Open the PDF in Google Chrome (drag the file into a Chrome window). Chrome's PDF rendering is more permissive than most readers. If it opens, use Ctrl+P (or ⌘+P) → Save as PDF to re-export a clean copy. This trick fixes a surprising number of "corrupt" PDFs.
7. 7
   Repair PDFs with online tools

   If Chrome's trick fails, try the free PDF repair tools at iLovePDF Repair or Sejda. Both are free for files under 10 MB. Don't upload anything sensitive — these are commercial services that store your files temporarily.
8. 8
   Recover photos (JPG, HEIC, PNG)

   First try opening in an alternative viewer (IrfanView, XnView, Apple Preview, GIMP). If only the thumbnail renders, the file's EXIF preview survived but the main image data is damaged. Free tool JPEGsnoop can analyze the file structure. For Apple HEIC files, converting to JPG via Preview sometimes works around format issues.
9. 9
   Recover videos (MP4, MOV, AVI)

   Try free repair tools untrunc (open source, requires a reference healthy file from the same camera/encoder) or Stellar Repair Video (paid, free trial scans the file). VLC also has a built-in repair: open the broken video, accept the "corrupted index" prompt, and VLC will attempt playback while reconstructing the index.
10. 10
    Try a previous version (Windows)

    Right-click the file → Properties → Previous Versions. If File History or System Restore was running, Windows may have an older clean copy. Restore from there.
11. 11
    Try Time Machine (Mac)

    Open the folder containing the corrupted file in Finder. Click the Time Machine icon in the menu bar → Enter Time Machine. Browse backward through time and restore the most recent uncorrupted version. Requires Time Machine was previously set up.
12. 12
    Use cloud version history (Drive, Dropbox, OneDrive)

    If the file was synced to a cloud service, log in via web. Right-click the file → Version history (Google Drive) or Activity → Restore (Dropbox) or Version history (OneDrive). Most services keep 30–100 prior versions for free. This is often the fastest recovery path.
13. 13
    Use data recovery tools as a last resort

    If the file is gone from disk (not just corrupt), tools like PhotoRec (free, open source) or Recuva (free for Windows) scan raw disk sectors. PhotoRec is the most powerful free tool but command-line driven. Stop using the affected drive immediately — every write reduces recovery chances.
14. 14
    Know when to stop

    If structural-repair tools fail, cloud version history is empty, and there's no backup, the file may simply be unrecoverable. Paid recovery services exist (DriveSavers, Ontrack) at $500–$3000 per drive, but they help with hardware failure, not corrupted bytes. Decide whether the file is worth that price.