Unfortunately, when you buy a new drive these days, there is always a risk that it could be a Fake. These drives are labeled with a much larger number of bytes than they can actually store. Then, even in the drive properties, it shows the fake capacity. When writing to it, everything looks good at first, but when you want to save a lot of data, it overwrites themself again. Very perfidious. The bad thing is that you sometimes notice it much later, or even not at all. That's why in Mighty Desktop we have built in the function Test Drive Capacity that completely writes the drive with random data and checks if everything is still there. You should do this right away with every drive you bought new.
As a positive side effect you also get the actual amount of user data that can be stored on the drive. On the one hand, a drive often has a somewhat smaller amount of maximum capacity than it says on it, and on the other hand, the administrative structures always take away a small amount of data.
Furthermore, the test also detects defective blocks. If it does, the test is aborted and the drive should be checked and repaired by the program that can be downloaded from the manufacturer.