I have fallen for the format trap. (like many many many before me thinking Sandisk was a good and reliable brand)
There was ZERO WARNING NOT to format your USB drive.
It was NOT on the packaging nor is there anything on the Sandisk website warning people NOT to format their USB drives.
Well, I formated it and guess what.
Writing speeds are now around 50 kBIT per second.
So transferring a 1GB file takes HOURS.
Thanks, Sandisk for this worthless piece of junk with ZERO backup.
No restore software no nothing.
You buy, you are screwed.
My advice is to stay away from SanDisk.