Okay people, I was too a victim of this memory card being fried off by SGS3 issue! I'm not 100% sure if its a fake card because I bought this originally for my
Blackberry curve from amazon.co.uk in June 2012, and then I started using the same SD card in my SGS3 in Jan 2013, without any issues until 2 weeks ago where it all began...
What caused the problem (in my opinion):
Well I'd imagine that it may have been an overheat issue, since I always leave my phone on charge overnight & making use of WiFi Tether whenever i'm out and about
(also when its plugged in on charge i'd make use of WiFi tether) and the phone would get really hot to a point I had to check if somethings on fire (the SD card slot area as well as SIM card slot were too damn hot too, let's say way beyond average temperature).
How it all started:
Completely random guess but it could also be that my SGS3 was unable to cope with a 32 GB sized memory card that had (12.1 MB free out space out of usable 29.7 GB), then again I might be totally wrong
It all started off randomly on a perfectly normal day, when nothing was being played or accessed from SD card, until I started to receive SD card related messages in my notification area claiming something like this "SD Card was unplugged/unmounted", and kept on coming back and un-mounting by it self something i'd refer to as an infinite loop..
at that stage only if I had realized this issue was common amongst others out there (such as topic starter of this thread).. I would have had my memory card backed up immediately. but me being silly, kept on ignoring it for good 20 mins, as I was still in middle of my lecture and thought huh? ill sort it out after the lecture, and this was my fault..
I started tackling the rescue options I had available and gathering tools to recover some of my important data, if I was forced to format the card.
I plugged a USB cable into my SGS3 to see if it would pick my memory card which turned out to be a fail, then I tried it with my Kingston USB SD card reader, at first I was happy seeing "Removable Disk (F):" under My Computer until after I was prompted to forcefully format my card before accessing it (common problem when file system is croupted which forces end users to format the medium before it can be accessed again), also which turned out to be yet another fail attempt as I got an error back saying "Windows was unable to complete format" even until this stage i did not completely give up i tried SDformatter Ver 3.1 even with this I had no luck or success, reaching this point I kind of gave up seeing no resolution available to my problem, as other people too had very similar problem claimed on numerous android related forums (so as the good old XDA forum)
but I decided to wait for some sort of resurrection or a miracle to take place, which would hopefully bring back my SD card back to life..
and that some sort of "Miracle" took place this morning (Hence, the reason why I'm writing this report, I'm really sorry about my English & Grammar btw.. I know it's terrible xD)
so as I woke up this morning, first thing I did was check my phone (again my phone was left on charge overnight) back of my phone was hot again, I started seeing my memory card coming back to life again, I was so chuffed at this moment..
The notification messages I received in my notification area was either "SD card found" or "SD card mounted", then "checking for errors" notification came on etc etc and it disappeared again.. then came back shortly after where I was able to perform full backup of my 29 GB worth of data using Android and Kingston card reader (for testifying)
reasons. All the data was backed up successfully apart from (some files being damaged mainly (.Mp3) formats having minor glitches through out the play and a change in it's HASH value, as I performed Md5 checksum on various (.Mp3) files comparing it to the copy of the same (.Mp3) file that I had a backup of on my notebook's HDD which also resulted in a mismatch, but none of my pictures were damaged and I didn't have a backup of my pictures at first so a HASH value comparison wasn't even questionable.
so few hours later, I started listening to some music on my SGS3 (.Mp3')s stored in Ex-SD card not the built in flash storage), and i started receiving SD card related messages in my notification area again, after a while it started to disappear by itself and kept on coming back and going, again and again.. (up-till this point I was able to access my data just fine as long as it remounted by its self)
Last resort:
finally decided to perform a full format on the card under NTFS, Fat32 and exFat and restoring some of my music on it to test with, and again same keeps happening being spammed by android notifications..
funny thing is that my other memory cards works just fine, so its not a simple matter of my SD Card slot being physically damaged.
Evaluation:
I think this issue is quite big and not being treated right, specially those who simply didn't come across it yet wouldn't know much about where to start the investigation, Samsung would obviously not admit it as being a problem from their ends, even if it was just a faulty batch on certain boards..
Heads up to people who have had similar problem, don't loose your hope just yet.. your data might still be on the card just wait for your SGS3 to be in a good mood one day and keep it plugged in and carry your notebook + a USB cable/SD card reader, its very much recommended because if it comes back to life for a short period of time , you should be glad and make most of it as that might be your final/last chance of acquiring your data back
Extra tests:
using H2testw, after performing the (NTFS) format I tried writing maximum data to available space on the same 32 GB SD card of mine, surprisingly it got stuck at approx 10% and here's the error code:
Error writing file 'F:\6.h2w', offset 0x1b700000.
It is still possible to verify the test data written up to this point.
(The system cannot find the file specified. Code 2)
Warning: Only 30341 of 30432 MByte tested.
Writing speed: 3.33 MByte/s
H2testw v1.4