Refuse the format. In the great majority of cases your files are still there : it is only the table of contents that is damaged.
A USB stick stores two separate things : your files, and an index saying where they are. When that index is damaged, the system can no longer read the stick and offers to start it afresh - which would erase precisely what you are trying to save.
The most common cause is removal during a write : the stick is unplugged without using the eject option, while a copy is still running in the background. Then come power cuts, knocks, and ordinary wear - a cheap stick used daily has a limited life.
Do not format it. Do not run the Windows check-and-repair tool on a medium whose data matters : it fixes the index by removing what it does not understand, and can permanently destroy files that were perfectly recoverable. The rule applies here more than anywhere : recover first, repair afterwards.
SD and microSD cards follow exactly the same logic, with one peculiarity : the small side switch on full-size SD cards. Pushed to the locked position, it makes the card readable but not writable, and produces misleading error messages. Check it before looking any further.
For photos, one important point : even after an accidental format in the camera, the images are often still recoverable as long as the card has not been used since. Stop using it immediately and take no more photos with it.
A stick advertised with a very large capacity and sold at a ridiculous price is sometimes doctored to report more space than it really has. All goes well until the real limit is passed : files copied beyond it are lost or corrupted, with no warning. If your problems appeared after filling a cheap stick, that is a serious lead.
It is a means of carrying files, convenient and fragile. It gets lost, breaks, wears out, and its electronics fail without warning. Documents that exist only on a USB stick are not backed up - see how to back up your data.
We handle USB sticks and memory cards as part of our data recovery service. The diagnosis says what is recoverable before you commit to anything.
A quick format only clears the index, and recovery remains possible. A full format rewrites the whole medium and makes recovery very unlikely.
That often comes from a drive-letter conflict or a faulty USB driver on the machine concerned. The stick itself is generally healthy.
A few years in regular use, less if it is heavily worked. Nothing warns you of the end, unlike a mechanical drive.
Would you rather we took care of it ? See our data recovery service, in Lyon and across the Rhone.
Do not format it : bring it in, your files are often still there.
Automatic assistant: it can make mistakes. Never share a password or a card number.
