[NAME]-Dean  I would install Windows on the mSATA drive since you have a 1TB drive for additional storage. The 250GB mSATA drive should have more than enough space for Windows and installing some applications. I would disconnect the 1TB drive before installing Windows. After Windows is installed, you can reconnect the 1TB drive, boot from the mSATA, and then reinitialize the 1TB using DiskPart. Here is the procedure for reinitializing a drive using DiskPart: [URL] Make sure you are booting from the mSATA, use the 'list disk' command to identify the 1TB drive, and the 'select disk' command to select the disk correct to reinitialize.  In Windows 10 it is easy to specify another drive for additional storage. Go to All settings / System / Storage / click on "Change where new content is saved" / then change where new apps, new documents, new music, new photos, new movies, etc. are saved. Note that existing documents, music, photos, movies, etc. remain in their current locations and have to be moved (copied to the new locations and deleted (if you wish) from the old locations. Existing apps have to be uninstalled and reinstalled, except that some apps prefer to be installed on the OS drive. Also, some apps default to saving content on the C drive.
"No Bootable Device Strike the F1 Key to Retry boot, F2 to Run the setup utility" I have a Dell XPS One 2720 AIO PC. I upgraded the pc with a Samsung SSD 850 EVO 1TB and a Samsung SSD 850 EVO mSATA 250GB. Windows 10 is installed on the 1TB. Everything is properly installed. Both SSDs are seen in the Bios. The CMOS battery has been renewed. The Boot mode in the Bios is UEFI, Secure Boot Control is Disabled. The first boot option is Internal HDD Devices, second USB Storage Device, etc. In the Advanced settings the Sata Mode is AHCI. Here it is also possible to choose the RAID mode. That seems to me no longer necessary because the startup of Windows 10 / PC is now faster with the SSD HD. I have already reinstalled Windows 10 once but the message No Bootable Device Strike the F1 Key to Retry boot, F2 to Run the setup utility keeps popping up. I think it has something to do with the settings in the Bios, or should I choose the RAID mode. If so, which settings are applicable. Does anyone in the Community know what to do.
XPS One 2720, boot issue, error below