My sd not responding
My Card is not allowing me move files onto it and I still have quite a lot of space on it
Backup / copy all files out as usual.
Use another computer to test out.
If the sd card protector switch is set to "not locked" and you are still having issues in formatting or writing new files, probably sd card is failing.
what brand is your sd card? is it micro sd, etc?
some brands have warranty covered for this. e.g. 3 years, 5 years.