I replaced a failing hard disk drive with a new SATA solid-state drive, but the computer will not boot without the old HDD connected. In UEFI mode it hangs in the firmware setup, and with legacy/UEFI enabled it shows "Reboot and select proper boot device." If I reconnect the old HDD, the system starts normally, even when I move it to a different SATA port. Windows itself is installed on an M.2 SSD, so the new SATA SSD is intended mainly as a replacement storage drive. What could be preventing the system from booting, and how can I fix it?
3 Answers
Check the old HDD in Disk Management while it is connected. It may contain the EFI System or System Reserved partition that your Windows installation on the M.2 drive is using to start. This can happen if Windows was installed while multiple drives were connected. The cleanest fix is usually to disconnect every other storage device, boot from a Windows installation USB, and repair or recreate the boot files on the M.2 drive. Back up your data first, since recreating partitions or reinstalling Windows can erase them.
Because Windows is already installed on the M.2 SSD, the new SATA SSD does not need to be bootable. Set the M.2 drive or its Windows Boot Manager entry as the first boot option in firmware, then confirm that the new SSD is detected there. Once Windows starts, initialize and format the new SSD from Disk Management. If it still refuses to boot without the HDD, the HDD is probably holding the boot partition rather than the operating system itself.
If you intended to move an operating system onto the new SATA SSD, copying files or using a basic disk mirror is not enough. You would need a proper disk clone that includes the EFI and recovery partitions, or perform a fresh Windows installation. For a fresh installation, disconnect the M.2 drive and all other storage devices during setup so Windows places the boot and recovery partitions on the intended drive.
That explains why the computer only starts with the old HDD attached. I’ll check which drive contains the EFI partition and repair the boot files with the other drives disconnected.