I have a sandisk ultra plus 16gb micro sd and it it used as a media storage device on my Samsung Galaxy S4. It worked fine until a few days ago. I go and delete files but when I go back into the file Explorer they are back. I tried it from the file Explorer on the phone (tried it with a galaxy s7 as well), connected it to the computer and tried it there and pulled it out and connected it to the computer directly and the same result every time. I tried to format it but it says that Windows cannot complete the format. When I connected it to my pc through the S7 I got the notice that the source was write protected.
I don’t know how it became write protected and wanted to know how to remove the write protection. It doesn’t have a switch on it and it is virus free.