Thanks very much for all info and the links. I won't be driving into the river anymore.
I used my iMac to download and unrar the files. I used a windows pc to format the card an copied the files using my mac again.
If you format the card on an iMac,use exfat and choose mbr. The system adds 3 files for spotlight. A finder app on mac. If you delete these files there won't be a problem switching from mac to windows.