The Dell XPS 15 9530 Laptop Supports Either 1 or 2 Drives Depending on the Battery Installed. (One 2.5" Solid State Drive or Hard Drive with the Smaller 61Whr Battery Installed and/or One mSATA Solid State Drive) or (One mSATA Solid State Drive with the Larger 91Whr Battery Installed) Note: Models that have the larger 91Whr battery installed do not support 2.5" Drives due to the larger battery occupying the 2.5" Drive bay. If installing a 2.5" Drive in models with the smaller 61Whr battery, you will need the 2.5" Drive caddy p/n 21YWY and cable p/n DG95V for installation.