Unable to format my memory card/SD - error -69877 couldn't open device I can't seem to able to format my PNY 32 GB SD card

When I go to Disk Utility and try to erase it gives me error: Unmounting disk, Couldn't modify partition map and operation failed

I successfully unmounted disk2 (the SD card) via terminal but when trying to erase it it shows  error -69877 couldn't open device

I also tried command sudo dd if=/dev/zero of=/dev/disk2 bs=1024 count=1024 but it shows permission denied

System: OS X El Capitan 10.11.6

Can you help please?
I had the same problem, but per this Mac Forum discussion, SanDisk Micro-SD to SD Adapters has a 'Lock&quot; slider that is easy to miss. After unlocking the card, I was able to reformat the microSD card with no problem.