My JVC everio GZ-VX715BEK threw up a 'Memory Card Error' out of the blue after 4 years of use using San-disk sdxc 64gb. I naturally thought the card had its day, but then found it readable via my laptop sd slot. I counted myself lucky that files were not lost, and purchased a replacement san-disk 64gb. To my surprise after inserting I got the same 'memory card error'! So I'm now worried the unit is the problem. I've done a factory reset, I'm unable to format the sd cards and this throws up 'format error'.
I did not find the right solution from the internet.