I bought a preformatted (NTFS) external drive and I want to re-format it with APFS using High Sierra (last upgrade). It is impossible. Whatever is the file system chosen, I always gat an error. What can I do? this is the second HD I bought. Different manufacturer, different capacity, but same problem. Thanks. Federico
sudo dd if=/dev/zero of=dev/rdiskX
whereX
is the identifier of the disk in question. You may need to issue the commanddiskutil list
to determine it if you don't know what it is. After that, try again.