Partitions or virtual mapping on device, not making file system

I am on Pi 3B+. Whenever I try to make a new img from sd card I get the error

mkfs.vfat: Partitions or virtual mappings on device '/dev/loop0', not making filesystem (use -I to override)

I am a newbie and not sure what I can do to fix this. I had it working once before but after a reinstall it has been acting up.