I have a WD passport external drive 750 GB. HDtune was shoring a pending bad sector- 'warning status. (just 1). So I ran a windows long format and I did a firmware upgrade too. After than HDtune is reporting a 'ok' status.

Can anyone tell me why this happened? I have attached HD tune reports after the format? - Are they normal? - should I still consider replacing it? - or is it back to normal now? - Please refer to the screen shorts. Can Somoen help me analyse SMART data?

Since attribute 0xC4 (Reallocation Event Count) and 0x05 (Reallocated Sector Count) are still zero, this means that the "pending" reallocation sector count attribute 0xC5) which you saw at 1 (and which is now 0), was not reallocated by the drive. This means it was (what is sometimes called) a "soft bad sector". I guess you did the long format using Win 7 - is that correct?

I see nothing in that SMART data to suggest that the drive has a problem but, as always, drives can fail without any warning. Therefore always make sure that you have backups of any data which you don't want to lose.

One more question: What procedure do you follow exactly, before you unplug that drive? Or do you always leave it attached to your PC / laptop?

Yes I did use windows 7 long format.Well, I did unplugged it once or twice cold turkey as i was not able to safely remove it. It could have been that. What is a soft bad sector, if you may?

When a drive is unable to read a particular sector, it marks it as "pending reallocation". The next time the OS writes to this sector, the drive knows that the existing data are no longer of any importance, so it retests the sector. If the sector tests OK, then it is returned to service. OTOH, if it tests bad, then its LBA is reallocated to a spare sector, and the SMART Reallocated Sector Count attribute is incremented.

AISI, possible reasons for a "soft" error could be that the original data were written slightly off-track as a consequence of vibration, or perhaps the data were written during a "High Fly Write" condition. Or maybe the data were affected by magnetic decay.???

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A backup a day keeps DR away.

Thanks, that would have written to all sectors in that partition, and therefore I'm assuming it also wrote to the "pending reallocation" sector as part of that process (although there are rare possibilities where there are exceptions to that).


fzabkar has explained the basic principle (there are additional fine details too), but there is a specific possible cause which wasn't yet mentioned (see below).


The SMART data suggests that it has been unplugged "unsafely" much more than "once or twice", which is why I was asking for your exact procedure.

Out of 250 power-cycles (attribute 0x0c), 231 of the power-offs were done when the drive was not prepared for that (attribute 0xc0) ie unsafe. One way of causing a "soft bad" sector, is for the drive to lose power when doing a write.

Unfortunately you haven't answered my earlier question about the exact procedure(s) that you use for unplugging, to see if a reasonable explanation for so many "unsafe" power-offs could be found. If that's not important for you, we can stop the discussion here

Hi As for the HHD, i only used for maximum of 50 instanaces, and yes Ihave unplugged it unsafely frequantly as it failed to detach safely.But i am 100% sure that I didnt power cycle it 250 times. I have two more external drives so I use this sparingly. I am surprised.

Doing that may have been related to the "soft bad" unreadable sector, which was not reallocated (i.e. the media tested OK when it was re-written), as I explained before. I suggest that you investigate why you are unable to detach the drive safely.


I'm just using the information collected by the drive about its power-cycles. I can think of a couple of reasons why that count might be higher than expected, but I'm not going to try to guess about this any more remotely.

Yes i willl trymy best to remove it safely, could it be the windows search reading it to the HDD, that prevents it from being detached safely? - whats if i shut down the machine? will it help?

I don't know - I don't provide Windows support. All I can say is that on those occasionals when I have been using Windows, if it reported a drive as unable to be safely removed, it was for a good reason. Your challenge is to find the reason for this behaviour on your PC, but this is not a hard disk fault.


I expect so - why not try it and see? With Windows running, gather the SMART data from the drive; shutdown the PC (with the WD drive still attached); wait 30s; start the PC again; when Windows has booted, then gather the SMART data again; compare the value of attribute 0xc0 (Unsafe Shutdown Count) in the first & second sets of SMART data - did it increase, or is it the same?