are you using PC or MAc?
on PC i insert the card,
i locate the card in win explorer, right click, and select format,Â i do not use any additional software to do this.
then i write the card which depending on the file and your machine can take a while, ive not seen a 15 hour write personally though unles the speed of your card is bad,
what “class” card(s) are you using? just curious.