I finally ended up having this issue on a Team Group 64GB microSD card. I could delete files, and they would show deleted until the card was reinserted and those files were back. No delete or write operations could actually occur.
Same issue when formatting with Windows, it cannot complete the format.
It was as if the card had been rendered "read-only" somehow.
I contacted Team Group, got an RMA#, and sent the card back to them and received a replacement on warranty. They were very prompt and fully admitted this was a failure of the controller on the SD card.
After one more week of use on the replacement card, it happened again. I contacted Team Group, got another RMA, and sent this one back. This time they asked for a lot more information, such as how I was using the card, what equipment/electronics it was being used with, etc. They contacted me back after another week of having the SD card back, and stated the issue was with a faulty design in the controller which made it incompatible with certain products, one of which being the particular model of cell phone I was using it in. This time they replaced it with an "upgraded" product that had a proper controller. Been using it for over a month now with no issues. The first 2 both failed in the first week. Hats off to Team Group for actually following through and taking the time to research what was going on on their end to get the problem fixed properly.
More than likely, each of you are having a similar issue. Team Group actually switched me to an SD card manufactured by SanDisk to get around the problem, because apparently their lower end class cards just weren't up to par.
Hope the problems I finally encountered, and the pains I took in getting it resolved, will help someone else.
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