Bad USB not recognized by Finder
Solution 1:
When I run into this kind of problem, I first identify the device with:
diskutil list
(e.g., /dev/disk3 -- BE SURE TO GET THE CORRECT DEVICE OR YOU WILL HAVE DATA LOSS)
Then I use the dd
command to zero it out.
sudo dd if=/dev/zero of=/dev/disk3 bs=8M
I hardly ever wait to completion, rather just a few seconds (maybe 10-15) and then press Control-C to stop it. This is just enough to wipe out everything at the start of the device that tells how it's formatted.
At that point, I go back into Disk Utility, insert the device, and repartition it, putting on a new formatted filesystem.