In 2011, I bought 2 units of WD My Book Essential 2TB external HDD to backup my working files.
Unit A is being used at least once a week for backup, while unit B is not being used regularly, probably just a handful of time 2-3 years ago.
Now that unit A is full, as I took the unit B from the cabinet and connected it, it doesn't seem to be recognised:
• I got the pop-up message saying the device is ready to use.
• It appears in My Computer, but without the capacity information. Double clicking it doesn't open it, just the green loading bar.
• It appears in Device Manager under "Disk drives", but under "Other devices", there is a "WD SES Device USB Device" with yellow exclamation mark.
So today I bring it to the computer shop, same problem. The technician said the HDD is dead and there is nothing can be done.
My first question: How possible is it that a HDD that's rarely been used will die for no reason?
Weird enough, after I reach home and try to connect the HDD again, this time I get the scan the disk to fix problem message (can't remember the exact message), and after the scanning is completed, the HDD just works as normal!
My second question: How can I be sure whether the HDD is really healthy?
I'm hesitated to use it, worrying it may be dead again anytime.
Anyway, the computer shop technician suggested that I should get a mobile HDD instead (which does not require power input) since I'm only using it for backup purpose, and it's slightly cheaper (not much though).
My third question: Practically, what are the differences between the two types of external HDD (one needs external power and one doesn't) ?
Thanks in advance.
