Although hard drives generally only sit around 8-12 W, their startup surge could be considerably higher. Maybe it's tripping the over-current protection in the PicoPSU.

Edit: And it's also very possible that power brick only does 30 W rather than 60 W. The Chinese are known for...creative use of ratings.

[ Edited by KennyR 31.07.2019 - 17:54 ]