Documents copied from an SD card or Android phone to a PC won't open — Word/Excel report the files are corrupted, or files that were fine on the phone are unreadable after the transfer

What's actually wrong

Phone-to-PC copies go through MTP, a notoriously flaky protocol: a loose or charge-only USB cable, an interrupted transfer, or unplugging before the write-cache flushes can silently produce damaged copies. The other possibility is the card itself — failing flash sectors corrupt files where they sit. Crucially, the copy on the other device is often still healthy, so your first move is re-copying by a more reliable route, not repairing.

Free fixes — try these first

1. Re-copy from the source by a better route. If the original still opens on the phone, don't trust the same cable/MTP path — put the SD card in a USB card reader (or use the phone's own "share to email/Drive" for the few files you need) and copy again.
2. Swap the cable and mode. Use the data cable that shipped with the phone, plug into a rear USB port, and make sure the phone is in File Transfer (MTP) mode, not charging mode. Many third-party cables are charge-only or drop bits under interference.
3. Compare file sizes. A transferred file that's 0 KB or smaller than the original never finished copying — the fix is re-transfer, not repair.
4. Check the card's filesystem. With the card in a reader, run chkdsk X: /f (X = card letter). This repairs directory damage that makes intact files unreadable. If the card is showing physical failure (very slow reads, disappearing files), stop writing to it and copy everything off first.
5. Open and Repair the transferred copy in Word/Excel: File → Open → Browse → arrow next to Open → Open and Repair.

If the free fixes fail

If the card is dying and every copy you can extract is damaged — or the phone's original is already gone — free methods run out; our analyzer reads whatever structure survives in the damaged copy and shows the honest percentage of content that can be rebuilt.