Android-to-microSD Transfer Left Partial JPGs and Broken MP4s: Check Data Before Repair
Normal-looking file sizes do not establish that a photo or video still contains real image or video data. If some files copied to a microSD are partly readable but later JPGs and MP4s contain no recognizable media headers, stop writing to the card and look for a valid original copy before paying for file repair. A counterfeit-capacity or failing card is possible, but this particular card has not been independently proven fake.
In this Android-to-microSD transfer case, the owner moved files from a nearly full phone to a 128GB SanDisk card formatted as portable exFAT storage. Some JPGs were partially readable and all videos were damaged. CHKDSK /f /r changed nothing. The owner had already made a card image, scanned it with DMDE, and checked sample files whose data did not resemble usable JPG or MP4 content.
Where Is the Last Valid Copy?
Keep the original card and the existing image unchanged. Check the phone’s current photo folders, app Trash or Recently Deleted where applicable, Google Photos and other backups, and any earlier computer imports. If an intact file exists in one of those locations, export that original to a healthy destination. Google’s Files help distinguishes moving files from copying them; a move should not be treated as an independently retained backup.
If the only surviving instance is a card file full of unrelated bytes, renaming the extension or rewriting an MP4 header cannot recreate the original photo pixels or video frames. Re-scanning an existing image may find some overlooked valid content, but a different scanner does not restore physical bytes that were never stored correctly or have been overwritten.
When Is a Counterfeit Card a Plausible Explanation?
A pattern of good early files, a partially readable image, and many later files with invalid payloads is consistent with storage that may misreport its usable capacity. Controller errors and transfer failures can also produce corruption, so the pattern alone is not conclusive.
Protect the Only Copy
Do not run capacity-testing or write-verification software against the only card before recovery decisions are complete. Heise’s H2testw documentation explains that a full capacity test writes files across the storage. Any destructive validation belongs after preservation, not before.
The result that matters now is whether a complete JPG/MP4 exists in the phone, a backup, or the preserved card image—not whether a file explorer still shows a plausible file size. If no correct media data survives, ordinary recovery and file repair cannot supply the missing content.