Suddenly Carbide 8GB will not open:

For something like this, I'd recommend doing encrypted backups. The built-in tool doesn't, but Toucan and some other utilities do. I may add them to the platform at some point, too.

It sounds like the drive controller may be dead (based on my non-hardware-knowing guess). So, the data is inaccessible. Even the manufacturer can't open the drive to repair or replace it due to the security. The drive is filled with epoxy (the most expensive part of construction) so just opening it rips the chips apart.

As it has a 5 year warranty, you can send it in to exchange it for a new one through CustomUSB's customer service.

John,

Thanks for your reply.

We now have two of these defective, one on arrival and now a second one dying.

I did communicate before with CustomUSB but I think they are full of it in terms of what they promise versus what they deliver.

Page http://worldsbestflashdrive.com/ says "If you'd like to exchange or return your order, please email store@customusb.com and we will email you a prepaid shipping label. That’s it, it’s that simple!"

I did that soon after receipt regarding the defective-on-arrival drive, and had to e-mail store@customusb.com more than once to get any reply, and then more again to get anything like a proper reply. Then the reply was super-casual, "so just send it back". No RMA number, no pre-paid shipping label, no nothing. At our expense.
I don't trust this "process". I get the impression that the e-mail support is outsourced to somewhere that doesn't care too much about the brands involved, and communication is poor. Also, I note that they use the one e-mail address for all purposes, so maybe warranty/return correspondence gets lost in the spam and noise.

I found it all a bit hard at the time and left that defective drive aside for later.

And on page https://store.customusb.com/info/ they say "Every order goes a through rigorous quality control process before being shipped from this location. Not that you asked about that part"
I don't think so. One drive had an obviously-defective pinpad button immediately detectable by just pressing it. Why do they talk about quality control when there isn't the most basic of such on an expensive drive like this ? (Or perhaps they quality-control the "order", but not the product.)

Regarding the second failed drive, I don't know (since the store gives no guidelines on the site nor by e-mail) what proof they need that the drive is defective. This drive works maybe one time in 10, and the failure occurs after it is unlocked with the PIN. Right now it is not responding at all, and I am unwilling to give anyone the PIN so they can test it is the same manner we experience the failure. Either they will have to take my word for it, or otherwise enter an incorrect PIN 10 times and have the encryption reset in order to test it, at which time I have no idea whether it will test as defective or not.

As a matter of interest, the failure symptoms are as follows:
1. unlock with the PIN as usual: the "open padlock" light starts flashing green as normal;
2. insert the drive into a USB port;
3. The "padlock open" light starts glowing continuously;
4. At this point, normally the blue data light should start glowing, but in the failure state it never glows, just stays dark, and Windows does not respond at all - Windows sees nothing, no device.
After some seconds the drive gives up, not having detected a USB port, and the two padlock lights flash red and green and then go dark.

When the failure condition is present (increasingly over time, and almost permanently now), this happens on all USB ports on multiple PCs, whereas the same USB ports having other USB drives inserted respond immediately and normally. It is not the computers, and not the USB ports.

Interestingly, I have managed to trick this drive into working. I PIN-unlocked the drive and then unplugged an active USB mouse and quickly plugged the Carbide into the USB socket which had just been active with the mouse, and it worked as normal. I'm not sure if this trick is fully repeatable. Once withdrawn and re-tested normally, it failed again as usual. Currently this is the only way to get this drive to work.

We have zero data loss because we back up obsessively after every data update. Backing up in a secure manner is a pain.
I tried your suggestion to beeje of possibly using Toucan, but found it a bum steer, I'm afraid. Toucan either does backup, or it does encryption, replacing files with encrypted copies of themselves in place rather than producing an encrypted backup archive as such, and this is neither easy nor obvious to manage in Toucan.
I think that something more like an encrypted 7Zip which could be run from the PA menu like the current unencrypted PA backup would be better, as long as it wrote the output file encrypted and did not leave unencrypted temporary artifacts lying around.

Thanks again. I'll have to take my chances with CustomUSB, but I am not confident I'll see these drives again once I "just send them back". These drives have cost a lot of wasted time.