I have a SanDisk Ultra USB 3.0 64GB. I have loaded files and viseos and used them without any problem. Now I cannot access anything when I insert the stick into my computer. Nothing registers and I cannot format. This is the second time this has happened. I have not conciously done anything. I have left the stick in the PC for a length of time without using it. What is wrong and can I retrieve the data? It is not so important that I would pay for help.
Just a guess, but maybe something has gone wonky with the USB port. Have you tried re-booting the computer and then inserting the flash drive?