Hi,
I really doubt that SYNC can cause hardware failure, but I've seen such issues many times, I hate when they get in locked state (think that there was a debate about manufacturers that do that), usually there is possibility to reformat them and I've done it several times. And for the one that is not detecting at all most probably the controller chip died and do not init the drive.

MMW do not do anything more than say Windows to write files on drive eg. we do not use any special way to copy tracks except system own commands.

EDIT: I have 6-7 SDcards that died over the years even as they say they had Lifetime guarantee. I guess their lifetime was bit shorter. It took me years to adopt SSD due the fact I was working on HDD recovery and basically from HDD you can always reconstruct data. From Fried Chip hardly.

2 of them locked up, I couldn't write anything or reformat them. The other one just doesn't get detected at all. I tried all of them on multiple (Linux and Windows) computers to no avail.

Hi,
Can you describe Broken? Do not recognize/show in device manager? Empty? Not Formatted? What happen when you insert those USB in PC?

Let me preface by saying this might be purely coincidence, but this is the third time that I've had a flash drive permanently broken either during or immediately after syncing with MM. Has anyone had this happen to them? Or am I just very unlucky?