I have done the installation of Ubuntu on the second hard drive, everything works fine but when I try to boot into Windows it gives me a blue screen with the error "INACCESSIBLE BOOT DEVICE".
After researching a bit I think I've found the problem with my setup but instead not find a solution.
My Pc is an HP envy 15 series, with a primary SATA SSD (Windows drive and other Linux partitions) and the new secondary mSATA SSD (where I would only install Ubuntu), I found that other people have my same problem but I have not really understood how to solve it.
The problem seems to be that Windows tries to use the mSATA SSD as cache drive, so it tries to access to it during the boot sequence and gives me the error said before.
All the partitions are fine, if I remove the mSATA SSD Windows work like before and the data has never been touched during the installation of Ubuntu (because I removed the Windows SSD during the installation to avoid mistakes).
Maybe a solution would be to install Ubuntu on the mSATA but install the grub on the Windows SSD but I think it won't solve the problem.