Unusual microSD card behavior. Data keep reappearing?
June 19, 2020 11:31 AM Subscribe
I have a 128GB Samsung EVO microSD card. I used it without incident in my Nintendo Switch for a year. I recently upgraded and put a larger microSD card in the Switch, so it was time to reformat and repurpose this one. Then things got weird.
This card has a single folder in root, named "Nintendo". That folder contains three sub-folders, "Album", "Contents", and "save". The folders contain, according to Explorer, 243MB, 114GB, and 385MB of data respectively.
If I delete these folders via Windows Explorer, I see roughly 115GB of data discovered and then successfully deleted. The card now shows "This folder is empty" when looking at the root in Explorer. There is NO DATA in the Recycling Bin at the end of this operation. The option to empty the Recycling Bin is greyed out.
If I remove the microSD card and reinsert it, all of those files are there again.
Win10 will not format this card via Explorer. I'm getting "Windows was unable to complete the format". Running CHKDSK via an admin command prompt shows no damage to the card. I attempted to format the card via the Disk Management panel and after 10 minutes we had recently gone from 0% complete to 1% complete.
I've downloaded the official SD Memory Card Formatter from sdcard.org and after running a quick format (which it reports is successfully completed) with that tool, the Nintendo files are still present.
There is an option to format via overwriting the card in that tool, and I am attempting that currently. Like the Disk Management attempt above, after about ten minutes we are 1% done. I'll just let it run and check on it from time to time and see if that resolves the issue.
But seriously, what the heck? What is going on?
This card has a single folder in root, named "Nintendo". That folder contains three sub-folders, "Album", "Contents", and "save". The folders contain, according to Explorer, 243MB, 114GB, and 385MB of data respectively.
If I delete these folders via Windows Explorer, I see roughly 115GB of data discovered and then successfully deleted. The card now shows "This folder is empty" when looking at the root in Explorer. There is NO DATA in the Recycling Bin at the end of this operation. The option to empty the Recycling Bin is greyed out.
If I remove the microSD card and reinsert it, all of those files are there again.
Win10 will not format this card via Explorer. I'm getting "Windows was unable to complete the format". Running CHKDSK via an admin command prompt shows no damage to the card. I attempted to format the card via the Disk Management panel and after 10 minutes we had recently gone from 0% complete to 1% complete.
I've downloaded the official SD Memory Card Formatter from sdcard.org and after running a quick format (which it reports is successfully completed) with that tool, the Nintendo files are still present.
There is an option to format via overwriting the card in that tool, and I am attempting that currently. Like the Disk Management attempt above, after about ten minutes we are 1% done. I'll just let it run and check on it from time to time and see if that resolves the issue.
But seriously, what the heck? What is going on?
Is it possible that the card is counterfeit? Apparently counterfeit SD cards are extremely common, and they often have weird glitches because the cards report themselves as larger than they actually are.
posted by arcolz at 11:48 AM on June 19, 2020 [1 favorite]
posted by arcolz at 11:48 AM on June 19, 2020 [1 favorite]
To insert it in your computer, are you putting it in a microSD-to-full-size-SD adaptor? If so, is the readonly switch set? That could be preventing you making changes to the card contents.
posted by matthewr at 12:02 PM on June 19, 2020
posted by matthewr at 12:02 PM on June 19, 2020
Response by poster: The card is being placed in a microSD->USB adaptor, not a microSD->standardSD card adaptor, so no "read only" switch stuff to consider.
The card may well be counterfeit, but I bought it in a batch of identical cards directly from Best Buy and did "same day pickup", so they just walked to the shelf and pulled them off for me.
At the suggestion of my BiL, I booted into Ubuntu and attempted to format the card with gparted. The results of that are as follows:
========================================
GParted 0.30.0 --enable-libparted-dmraid --enable-online-resize
Libparted 3.2
Format /dev/sdc1 as ntfs 00:00:20 ( SUCCESS )
calibrate /dev/sdc1 00:00:02 ( SUCCESS )
path: /dev/sdc1 (partition)
start: 32768
end: 251131903
size: 251099136 (119.73 GiB)
clear old file system signatures in /dev/sdc1 00:00:00 ( SUCCESS )
write 512.00 KiB of zeros at byte offset 0 00:00:00 ( SUCCESS )
write 4.00 KiB of zeros at byte offset 67108864 00:00:00 ( SUCCESS )
write 512.00 KiB of zeros at byte offset 128562233344 00:00:00 ( SUCCESS )
write 4.00 KiB of zeros at byte offset 128562692096 00:00:00 ( SUCCESS )
write 8.00 KiB of zeros at byte offset 128562749440 00:00:00 ( SUCCESS )
flush operating system cache of /dev/sdc 00:00:00 ( SUCCESS )
set partition type on /dev/sdc1 00:00:04 ( SUCCESS )
new partition type: ntfs
create new ntfs file system 00:00:14 ( SUCCESS )
mkntfs -Q -v -F -L '' '/dev/sdc1' 00:00:14 ( SUCCESS )
Cluster size has been automatically set to 4096 bytes.
Creating NTFS volume structures.
Creating root directory (mft record 5)
Creating $MFT (mft record 0)
Creating $MFTMirr (mft record 1)
Creating $LogFile (mft record 2)
Creating $AttrDef (mft record 4)
Creating $Bitmap (mft record 6)
Creating $Boot (mft record 7)
Creating backup boot sector.
Creating $Volume (mft record 3)
Creating $BadClus (mft record 8)
Creating $Secure (mft record 9)
Creating $UpCase (mft record 0xa)
Creating $Extend (mft record 11)
Creating system file (mft record 0xc)
Creating system file (mft record 0xd)
Creating system file (mft record 0xe)
Creating system file (mft record 0xf)
Creating $Quota (mft record 24)
Creating $ObjId (mft record 25)
Creating $Reparse (mft record 26)
Syncing root directory index record.
Syncing $Bitmap.
Syncing $MFT.
Updating $MFTMirr.
Syncing device.
mkntfs completed successfully. Have a nice day.
========================================
Nevertheless, after this gparted still reported it as an unmountable exFat formatted device and after booting back into Win10 I can still see that damned Nintendo folder in root.
posted by radiosilents at 12:09 PM on June 19, 2020
The card may well be counterfeit, but I bought it in a batch of identical cards directly from Best Buy and did "same day pickup", so they just walked to the shelf and pulled them off for me.
At the suggestion of my BiL, I booted into Ubuntu and attempted to format the card with gparted. The results of that are as follows:
========================================
GParted 0.30.0 --enable-libparted-dmraid --enable-online-resize
Libparted 3.2
Format /dev/sdc1 as ntfs 00:00:20 ( SUCCESS )
calibrate /dev/sdc1 00:00:02 ( SUCCESS )
path: /dev/sdc1 (partition)
start: 32768
end: 251131903
size: 251099136 (119.73 GiB)
clear old file system signatures in /dev/sdc1 00:00:00 ( SUCCESS )
write 512.00 KiB of zeros at byte offset 0 00:00:00 ( SUCCESS )
write 4.00 KiB of zeros at byte offset 67108864 00:00:00 ( SUCCESS )
write 512.00 KiB of zeros at byte offset 128562233344 00:00:00 ( SUCCESS )
write 4.00 KiB of zeros at byte offset 128562692096 00:00:00 ( SUCCESS )
write 8.00 KiB of zeros at byte offset 128562749440 00:00:00 ( SUCCESS )
flush operating system cache of /dev/sdc 00:00:00 ( SUCCESS )
set partition type on /dev/sdc1 00:00:04 ( SUCCESS )
new partition type: ntfs
create new ntfs file system 00:00:14 ( SUCCESS )
mkntfs -Q -v -F -L '' '/dev/sdc1' 00:00:14 ( SUCCESS )
Cluster size has been automatically set to 4096 bytes.
Creating NTFS volume structures.
Creating root directory (mft record 5)
Creating $MFT (mft record 0)
Creating $MFTMirr (mft record 1)
Creating $LogFile (mft record 2)
Creating $AttrDef (mft record 4)
Creating $Bitmap (mft record 6)
Creating $Boot (mft record 7)
Creating backup boot sector.
Creating $Volume (mft record 3)
Creating $BadClus (mft record 8)
Creating $Secure (mft record 9)
Creating $UpCase (mft record 0xa)
Creating $Extend (mft record 11)
Creating system file (mft record 0xc)
Creating system file (mft record 0xd)
Creating system file (mft record 0xe)
Creating system file (mft record 0xf)
Creating $Quota (mft record 24)
Creating $ObjId (mft record 25)
Creating $Reparse (mft record 26)
Syncing root directory index record.
Syncing $Bitmap.
Syncing $MFT.
Updating $MFTMirr.
Syncing device.
mkntfs completed successfully. Have a nice day.
========================================
Nevertheless, after this gparted still reported it as an unmountable exFat formatted device and after booting back into Win10 I can still see that damned Nintendo folder in root.
posted by radiosilents at 12:09 PM on June 19, 2020
Response by poster: I'm now attempting to format it using a different microSD->USB adaptor because why not
posted by radiosilents at 12:12 PM on June 19, 2020
posted by radiosilents at 12:12 PM on June 19, 2020
Response by poster: Ahhhhhh, now we're getting somewhere. I downloaded an app to test the microSD's capacity, a tool that can and is used to detect fake cards, and at the very least I'm getting a pile of errors and "The media is likely to be defective", SO I'm gonna call it a loss and get on with my life.
Boo.
posted by radiosilents at 12:20 PM on June 19, 2020 [1 favorite]
Boo.
posted by radiosilents at 12:20 PM on June 19, 2020 [1 favorite]
What is going on?
The card is accepting writes from the OS and is not reporting errors when doing so, indicating that it is actually going through the motions of committing the written data to flash EPROM, but the internal erase/burn cycles are simply not doing anything because the flash medium has worn out.
I've seen this pattern on several Samsung SD cards that have been in heavy use. Not super impressed with the reliability of these devices. Samsung's SATA and NVMe flash drives are much more reliable than their SD cards.
For best longevity in any application where you need an SD card to accept a lot of writing, use a card sold specifically as a "high endurance" type and/or partition it in such a way as to use substantially less than its stated capacity.
posted by flabdablet at 12:56 PM on June 19, 2020 [5 favorites]
The card is accepting writes from the OS and is not reporting errors when doing so, indicating that it is actually going through the motions of committing the written data to flash EPROM, but the internal erase/burn cycles are simply not doing anything because the flash medium has worn out.
I've seen this pattern on several Samsung SD cards that have been in heavy use. Not super impressed with the reliability of these devices. Samsung's SATA and NVMe flash drives are much more reliable than their SD cards.
For best longevity in any application where you need an SD card to accept a lot of writing, use a card sold specifically as a "high endurance" type and/or partition it in such a way as to use substantially less than its stated capacity.
posted by flabdablet at 12:56 PM on June 19, 2020 [5 favorites]
Yeah, those things are unreliable: Bunnie Huang "On Hacking MicroSD Cards"
posted by at at 1:55 PM on June 19, 2020 [3 favorites]
posted by at at 1:55 PM on June 19, 2020 [3 favorites]
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posted by radiosilents at 11:37 AM on June 19, 2020