Q: Porsche Design Mobile USB 3 stopped mounting on all my computers (MAC)...  Its just over a year old.

Not sure what to do at this point.  The HD is just over a year old.  I have other lacie hard drives and haven't had a problem to date.  This one will no longer mount.  Ive tried updating the lacie software to no avail.  My older mac which isn't updated to El Capitan didn't mount the HD either.  My other two macs (IMAC, Mac Pro) are updated and run El Capitan.

Help