Puneet Ghanshani

Chief Architect at Microsoft

5 minute read

I recently faced a situation that my external hard disk that I used as a backup drive started giving me bad sector issues.  I ignored the early warnings until I released that the occurrence of these issues had increased.  I used several applications to recover the files but no software could guarantee 100% recovery.  When the problem became terse, there wasn’t any easy relief!

I wasn’t able to browse my disk and I was prompted ‘Format E:\ drive’  -- a solution that was unacceptable to me.

If you are facing this issue, then this article should help you!

Resolving the Format E: drive and access issue

As advised on many websites, I started with chkdsk on Command Prompt (with Run As Administrator option) on my Windows 8 laptop.  This is a time consuming task so please keep some time at hand

chkdsk e: /f /r

Immediately I received the first error after which I abruptly stopped chkdsk.  The error was 

The first NTFS boot sector is unreadable or corrupt

Chkdsk utility will not be able to fix this issue.  The Windows NT version 4.0 file system keeps a duplicate copy of the NTFS boot sector at the end of the partition.  So we still have a chance to recover the boot sector from the end and replace it at the first position.  To recover this, you need an application to do some magic for you.  After trying my luck with many promising applications, I found a very simple DOS-based utility that works wonders.

TestDisk: http://www.cgsecurity.org/wiki/TestDisk can be used to navigate to the disk, analyse partition (if any) and recover NTFS boot sector from backup. 

    run TestDisk,
    select the hard disk and the partition type
    choose Advanced
    select the partition
    choose RebuildBS

RebuildBS detected that there was a discrepancy between boot sector at beginning and at the end.  And then fixed it.  This will allow you to browse your disk from Windows Explorer

Fixing the bad sector issues

Now you re-run the following chkdsk command

chkdsk e: /f /r

Again, this is a time consuming task so please keep some time at hand.  It will fix any bad sector errors, missing file chains, etc and hopefully clean most of the issues.  However, there is no guarantee that the drive will never again have bad sectors

Data Backup

If your data is critical, it is advisable to retain another copy of it on a different drive.  There are many tools available to transfer your data from one disk to another.  But most of these tools get stuck when they face any bad sector.  I preferred to use some native tools in Windows 8 to do the initial data transfer.  Windows 8 comes with 2 handy tools – xcopy and robocopy.  I found robocopy much faster than xcopy.

The syntax for robocopy to copy contents of E: drive (the bad drive) to F: drive (new backup drive) would be

robocopy e:\ f:\ /MIR /R:0 /W:0

/MIR = Mirror entire directory structure (can use /E instead)
/R:0 = 0 retries for read/write failures
/W:0 = 0 seconds between retries

You can also use xcopy to do the same task

xcopy /C/H/R/S/Y e:\ f:\

/C = Continues copying even if errors occur
/H = Copies hidden and system files also
/R = Overwrites read-only files
/S = Copies directories and subdirectories
/Y = Overwrites existing files without asking

Hope this resolves your problems.

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