I to am having this issue with my 64GB Ultra Class 10 micro-SDCard. I use it in a Samsung Galaxy Note3, first with Kit Kat and now recently on Lollipop. When I first used it under Kit Kat I formated it and encrypted it to the device.
Per the upgrade instructions for Lollipop I decrypted my device and external storage before upgrade. Wanting a fresh start I backed up my data to my network storage and used Windows Powershell in admin mode and ran Diskpart executing the Clean All to wipe the card. It completed with no errors. But yet reinserting the card to my surprise showed the data was still intact, as if permanently baked into existence.
This actually worries me a bit, in regard to government spying on the public. It’s been long known with the advent of flash technology that once a sector of information was overwritten or wiped it was gone forever unlike traditional hard drives that can maintain a ghost trace of the information which was a cornerstone to computer forensics.
Makes me wonder if government has dictated a requirement that flash media also have this capability? Everything I’ve done to this SDCard should have permanently wiped the drive. Partion, volume and sector level data. My data permanently archived to the card all cause my Note 3 cooked itself a few times in my car dock all day as I ran service calls?
