Is my hard disk at risk? (Reallocated Sectors)


Jun 25, 2015
Hi all,

I recently faced low read and write speeds (1MB/s to 30MB/s) on my PC with Windows 10 (upgraded from Win 7), therefore I decided to do a fresh install of Windows 10 today.

After the clean install the reads and writes seems to be okay, I tested the speed by copying a 1GB video file from my external hard disk to my local drive and got around 70+MB/s, just to make sure I ran CrystalDiskInfo and shows the health status as "Caution" - 84 Reallocated Sectors.

What does this warning means? Will my hard disk fail in the near future?

Thanks guys!
While reallocated sectors are normal, the "84" here probably means 84/100, or 84% of all reserve sectors have been used.

If the drive is less than a decade old, that's an unusually high number for a drive that age. It indicates the drive's sectors have been failing at an unusually high rate since it was new, or the sector failure rate has accelerated recently and the drive will likely fail soon.

If it is about a decade old, that means at the average sector failure rate you only have 2-3 more years before all reserve sectors will have been used (assuming things don't get worse), and the drive will become unreliable because sector failures will result in data loss, and more annoyingly - disk accesses will get very slow as the computer has to keep trying to re-read failing sectors.

If it's more than a decade old, on top of the low remaining reserve sectors, the drive is outdated and slowing down your system.

So any way you cut it, JaredDM's assessment is correct. Time to replace the drive. If the number were smaller, say in the 60s or even 70s, I'd do a little more testing to see if this was just normal wear and tear. But 84 is getting to the point where you should start shopping for a new drive regardless.