Question Of SSD's & S.M.A.R.T. reporting errors.


Feb 15, 2014
Hoping someone can shed some light...

8 months ago I installed a 1TB Sandisk SSD in my Win7 desktop. Cloned the HDD to it. It worked great; I loved the speed increase. After install/cloning, I ran the sandisk utility once. S.M.A.R.T. info showed no bad blocks or errors; status was listed as "good". I've used the disk 2-4 hours most days since. Never looked at S.M.A.R.T. info again.

A month ago, I figured I'd clone the drive back to the old HDD just to have a backup of everything "as is", just in case. The cloning failed because of bad blocks on the ssd. I downloaded EaseUs Partition Master & ran a surface scan. It found 1665 bad blocks. I also downloaded Crystal Disk Utility. It also showed 296 "reported uncorrectable errors" in addition to the 1665 bad blocks.

Since then I've continued to use the ssd, and it's been working fine. I run Crystal every few days when I boot up and the number of bad blocks has stayed constant, but the uncorrectable errors increase every day. It's now at 2367. Oddly, the corrected block count is 0. I've been unable to locate any corrupted files, even after manually copying just about everything on the drive...just to try and find what might be corrupted (and yes, I've backed it all up). Googling the topic, pretty much all forum replies out there on similar subjects say that if there are increasing errors like that, the drive is about to fail.

But my questions are this: What exactly are the "uncorrectable errors"? Nothing I've read about S.M.A.R.T. attributes really gives a detailed explanation of exactly what might be wrong. And further, what good is S.M.A.R.T. technology if a drive can keep increasing errors like this, but drive utilities (Crystal, Sandisks own utility, etc) still report the drive as being in "good" condition?

I've been planning to replace this PC with a new one in the fall with Win10 anyway, so I'm just crossing my fingers that the ssd keeps functioning til then. But I would appreciate any input forum members may have on the topic. Much thanks.
To answer that question, it's probably good to go back to your original point and explain what a bad block is.

A bad block is also a bad sector - and it is effectively a sector on the drive upon which the OS - for either logical or physical reasons - was unable to read or write to that sector correctly.

In logical errors, this could be that the information on the cell did not correspond with what the OS expected, and it doesn't match the CRC error correction code, therefore the OS marks the sector as a "bad" - in physical cases, this can simply be the OS tried to read or write to it and was physically unable to (usually because of damage). So when the data fails to transfer, it can create an error.

Which leads you onto uncorrectable errors - which is basically when an error in the storage drive cannot be corrected by the inbuilt ECC (Error Checking and Correction) software/function - and when it can't be corrected by this, it can quite often mean there is a physical problem (If it logical, usually just writing over the sector will resolve it).