I have tried asking in Toshiba forums, manufacturer of the laptop, but I have not had any luck; therefore, I'll try seeing if anyone has any suggestions in here since the root of the issue is finding a driver that is compatible with the Intel infrastructure to see the drives during a Windows 7 installation.
I have a laptop, Toshiba Satellite U845-S406, that has a Hitachi 500 GB SSD drive and a SanDisk 32 GB SSD drive (as seen by the BIOS). From what I am reading in the Toshiba forums. The drives are in a RAID configuration and the 500GB uses the 32 GB as a swap drive. In the BIOS, it says that the system is using the Intel Rapid Start Technology. There are no options to switch the drives from IDE, SATA or RAID; therefore, I am restricted on the drive configuration.
The system was initially getting BSOD on the IASTOR.SYS while using Windows 7. It progressively got worse to where the system was not usable. I thought it might be a rootkit; therefore, I backed up what data I could and then tried to use the recovery partition on the drive. It came back with the same BSOD. Safe mode same thing. I wiped the drives of all data and partitions using GParted (Linux based). I tried to install Windows 7 but none of the RAID drivers from the Toshiba site are working. They will either show no drives or produce a BSOD on IASTOR.SYS.
My question for the Intel Community is how do I find out what Intel driver works with this system? Is there a bootable utility that will show me this? I am not sure what else to try. I have tried to install Windows 8 and Windows 10 thinking that maybe they would have more recent drivers that would be compatible but have had no luck. What puzzles me is how can I see the drives with GParted but I cannot see them with Windows installation? I have even tried to install Linux on the system but it cannot see the drives. For some reason only, GParted has something that allows it to see the drives.
What happens with the disks when you try to install Windows*? Are they visible to you during installation?
I see your system supports Intel® Rapid Start Technology but do not confuse with Intel® Rapid Storage Technology, which could be related to iastor.sys. I suggest you try with this version. You can even try to load it during the operating system installation. Another option would be using a software image from Toshiba*, just like what came preinstalled with the unit.