Windows 7 - Can Bad Sector spread from HDD to another HDD?

So i would like to know that can bad sectors spread from 1 hard drive to another hard drive? for example i have 2 HDD's and one of the drive has bad sectors which is connected through a USB Enclosure for a backup or is directly connected inside the PC as a secondary drive? can it spread and infect the other good drive?

If you have a hard drive with bad sectors it won't spread to another hard drive, but it will fail sooner rather than later.

My advice would be to backup anything valuable on the drive with bad sectors and get it replaced as soon as possible.

At the very least you should run Chkdsk in the hope it will find and recover any damaged sectors.

Disk Check

Well if a sector goes bad on your main disk under a piece of data, windows won't just read the mangled or missing data without error. So hopefully the backup software will get the error and skip copying a possibly bad file. Well the worst I could see happening is that it will copy the file up to the bad spot and stop, possibly shorting the file size on the copy on your backup.

Truthfully, I have no idea how many backup programs verify a files integrity before trying to copy it over a previous backup. Tools like SyncToy or RoboCopy probably do NOT. A GOOD backup program (if there is such a thing... CrashPlan?) might.

ok i have a spare old Seagate 80GB SATA HDD and i plugged it in through USB enclosure to check it. Actually yesterday i was carrying it in my hand and suddenly i dropped it and it fell hard on the floor upside down also it was making clunk noise on boot up before but it was my brother's old HDD. When i clicked on the Health tab in HD Tune it was giving warning status and the Reallocation Sector Count was highlighted i also did format (write zero) it when i connected it but it does'nt fix anything though there's nothing in the HDD and all i'm a bit worried if it would spread to the OS Drive.

Uh, no.

In fact, that drive is now complete recycle material. It can't harm anything but it's completely useless and shouldn't be hooked back up to a computer for any purpose anyway. If you manage to store anything on the drive it's probably as good as gone already...

oh i see but thanks alot fseal & seavixen32 for all the help

That's similar to asking if you have two cars in a garage, and one needs an oil change, will it infect the other car, requiring it's oil to be changed. Bad secotrs aren't a virus or other software....they refer to physically damaged or failed parts of the hard drive's platter. So, as mentioned, it won't "spread", but it would be a good time to think about backing up your data and checking the warranty status of your drive.

The bad sectors develop due to sudden jerks while the HDD is operating and the head bumping against the platter, damaging the surface. The hard disk platter at that location loses its magnetic properties and the area becomes defective.

Hence even though the head tries to write data on that sector, the data is not recorded correctly on the bad sector. During the verification process, the disk identifies this bad sector and will mark it as bad and will try to move any readable data out of the bad sector.

In subsequent writes, the cluster containing the bad sector is always skipped whenever the hard disk tries to write a new file in this location.

Once a defective sector is marked as bad, the hard disk will avoid this bad sector in all the disk operations.

Chkdsk program tries multiple times to read the information already written on the bad sector and tries to recover the data.

As the bad sector is a phisical error on the hard disk platter, this error is local to this hard disk only and will not be passed on to another good hard disk.

You don't have to worry about bad sectors filling the good hard disk from a bad hard disk.

thanks DeaconFrost and rraod for more detailed info much appreciated

CrystaDiskInfo is a good tool to monitor reallocated sector count over time and give a warning. This gives you a better idea when it's time to retire the HDD.
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