New
#21
jimbo45's last statement.
I created a similar situation on an Insider Preview computer with a 320GB and a 250GB HDD that had been working since joining the Technical Preview [renamed Insider Preview later]. I removed the 250GB D: drive and couldn't boot, checked the BIOS and it was set for AHCI/RAID, Win10 created the RAID setup using both drives. I reinstalled with only 1 drive connected and the AHCI was chosen then I reconnected the second drive later and all has been well since but if a reinstall becomes necessary I'll have to keep the process in mind to avoid the screw-up again.