Bests & Worsts Reviews from Amazon

We purchased about 20 of these SanDisk drives over the past three years, and about half of them have failed. I purchased again in October 2017 thinking SanDisk had fixed these problems, but the newest drives I've received also have failed. Either I get a "you must format the drive" while browsing files, or the contents just randomly disappear and the drives are inaccessible unless unplugged and replugged, and the same failures occur yet again. Overall I am disappointed with the purchases and have had to spend a significant amount of time and money replacing these drives with our clients. We have had much better luck with PNY drives, but even with spotty failures there I am switching over to 500 GB Toshiba portable hard drives, as it appears flash drive technology above 32-64 GB is simply not dependable yet.