External SanDisk SSD suddenly corrupt and unreadable for no apparent reason!

rishabhsingla

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Although my problem *seems to have been* solved, I would really want to know:

1) Why this happened in the first place?
2) How serious was/is the problem?
3) Has it "gone" or can it come back?

A bit background: I consider myself the type of person who keeps his computer system up-to-date and smoothly running in all respects. The OS and all applications are configured properly, all updates are always installed, the best UPS system in the market is attached, Kaspersky's Internet Security is always running, no useless applications are ever installed, and so on.

Why then did my external SanDisk SSD [it uses MLC-type NAND] all of a sudden, with no apparent reason, suddenly become invisible in My Computer [Windows 8.1]? I feared loss of invaluable ~250 GB of my data - documents, family photos/videos, business data, schooling/college data and tons of other stuff. I changed the external casing but the problem persisted. I connected the drive to a different laptop but the problem persisted. I feared the worst - that the disk's hardware and/or its file system had gone bad, and I might never get my data back [defeating the very purpose of buying a SSD in the first place - to safeguard my data].

Finally, it was the good old CHKDSK that came to my rescue.

Please see the screenshots.

https://imgur.com/a/YDfAk

https://imgur.com/a/zhmdA

Somehow it recognized that there was an attached drive and it repaired the file system and my data became visible again [not sure if any/some files were lost during the repair]. What I don't know is why this happened, whether there's any hardware fault hiding somewhere, whether it'll happen again, whether the NAND has developed issues. Right now I'm copying the entire disk to a spare 250 GB external Seagate drive that I have.

Please read the error messages in the screenshots and help!
 
1. WITHOUT FAIL, YOUR FIRST ORDER OF BUSINESS IS TO BACKUP THE CONTENTS OF THAT EXTERNALLY-CONNECTED SSD TO ANOTHER DRIVE.

2. The problem here is that you're working with a laptop so you can't copy/clone the contents of that USB externally-connected SSD to an internally-connected drive (if you were working with a desktop PC).

3. Presumably your laptop contains multiple USB external ports. That being the case, since the data on the present USBESSD is so valuable to you, I would suggest purchasing another USB external enclosure + another drive (HDD or SSD) and copy or clone the contents of the present external drive to the new USB-connected external drive. Obviously that would provide multiple backups of your precious data.

4. When your system contains data that is invaluable to you - as it is in this case - the ONLY answer is to create multiple backups of that data.
 

rishabhsingla

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Dear ArtPog, thank you for taking time to reply to my issue. Could you please, looking at the two screenshots, put some light on why this problem might have occurred in the first place? How serious was/is it looking at the CHKDSK error messages in screenshots? The files that CHKDSK repaired, they seem to be related to the MFT, how did these get corrupt when the last time I removed the disk, I chose 'Safely remove hardware'?

Thank you for your help!
 
In all candor, there's really no way to tell what precisely caused this corruption. Aside from the new backup (which should become your primary process at this point), you can test the SSD with SanDisk's Dashboard tool - https://kb.sandisk.com/app/answers/detail/a_id/15108/~/sandisk-ssd-dashboard-support-information to ensure the SSD is non-defective. It's probably OK, but check it out anyway.

Whether there's a problem with the USB external enclosure is really impossible to tell. There's really no test one can apply. Obviously if there are problems with various drives installed in the enclosure that's a clue. Generally speaking, they work or they don't work. There's usually no middle ground.

At this point just focus on creating multiple backups of your important data.
 

rishabhsingla

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Dear ArtPog, thank you for the advice. I just ran SanDisk's Dashboard tool thoroughly, including both the short and detailed S.M.A.R.T. tests, and the tool says that my SSD is alright in all respects. Makes me wonder how and why did I get so close to losing all the data! These electronic things are so unreliable!
 
Indeed. It's the primary reason why it's so critical for all PC users to create & maintain comprehensive backups of their system(s). One never knows when disaster can strike and that old adage - "be safe, not sorry" still holds.
 

rishabhsingla

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True. Two copies of everything are a minimum, I guess.
 

rishabhsingla

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I just ran CrystalDiskInfo 7.5.0 on my SSD and the result is nothing short of staggering! As seen in the screenshot [link below], the ratio of Total NAND Writes to Total Host Writes is an unbelievable ~181 times! I read somewhere that it's usually 2 or 3 or 4 times. But 181 times? What's wrong with my SSD?

https://imgur.com/a/tDHO6

I searched on Google and a guy who has recently posted on SanDisk's own forums is worried because his SanDisk SSD [same model as mine] has the ratio at 6.7. Now 6.7 is NOTHING compared to my ratio of >181. What are we looking at? An imminent crash?

http://forums.sandisk.com/t5/SanDisk-SSD-Plus/High-Total-Nand-Writes/td-p/362558

Please help!
 

rishabhsingla

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ASK THE COMMUNITY