You will need at least one of the hard drives when you start SW up, since it has to load into memory. So I would set up the computer so that the hard drives never turn off, at least not when you are plugged into the wall outlet (assuming you are using a laptop).
Thanks for your answer. I am NOT using a laptop. In my computer I have 2 SSD and 3 mechanical harddrivers. SolidWorks in installed on an SSD and all the files that SolidWorks uses are on the SSDs. No file, folder, etc is on the mechanical hard drives, I am using them for other software and for backup. The OS and all the drivers are installed in the SSDs.
It seems that, when SW starts, it need all the hard drives to be "active" and so it turns on all the mechanical hard-drives that are in a "stand-by" power and life saving mode. I would like to "tell" SolidWorks that it should not and doesn't need to turn on those harddrives.
I have notice this problem in 4 different workstation using SSD as primary (with SolidWorks installed) and one or more mechanical drives as backup disks, both with Windows 7 and Windows 8 (it seems that both of this OS will turn off the hds that are not used).
I know that the main stress for a mechancial harddrive is to be turned off and on (more than an "always" active state) so I am thinking about removing the power setting in Windows, but I have also to consider that the computer could stay for days powered on without the need of those mechanical hds.