I found a Lexar SD card in a workplace storage area that is labeled as 128GB, but Windows Disk Management only detects roughly 7GB of usable space. Several formatting tools have failed to restore the remaining capacity. Could the card simply have a small partition, or is it likely defective or counterfeit? I'd like to determine whether the missing storage can be recovered safely.
3 Answers
Also rule out the hardware being used to read it. An old card reader may not properly support newer high-capacity cards, so try a different reader or format it in a relatively modern camera. If multiple devices still show the same small capacity, the card itself is almost certainly the problem.
There’s a good chance it’s counterfeit. Fake cards often report a much larger capacity on the label while physically containing only 8GB, 16GB, or 32GB. If the official formatter and a capacity test confirm that the usable space is only around 7GB, there isn’t a way to recover the advertised 128GB.
It may just be partitioned to around 8GB. Try the official SD Association formatting utility first, since it handles SD-card alignment better than a normal quick format. You can also use DiskPart to clean the card and create a new partition, but that will erase everything. A full overwrite test may take an hour or more and will show whether the card can actually hold its advertised capacity. If it still reports only about 7GB, I’d discard it—especially since it was found in storage and shouldn’t be trusted with important files.

Related Questions
Lenovo Thinkpad Stuck In Update Loop Install FilterDriverU2_Reload