Unable to get Windows 10/ Windows 7 dual boot working

I have an OEM version of Windows 7 Pro installed on the HD of my Dell Precision desktop PC. I wanted to dual boot Windows 10 and Windows 7. I therefore bought a new Windows 7 Pro key and an SSD and installed first Windows 7, then (with difficulty; see below) Windows 10. The HD was offline throughout.

Post-install, I reconnected the HD. Windows 7 (on the HD) can see both disks but Windows 10 (on the SSD) can see only the SSD. I would like to know how to make both disks and O/S's mutually visible so that I can boot either, as desired.

Sequence of events:

1. A new SSD was attached to HDD0 and partitioned. A new instance of Windows 7 was installed in partition 1.

2. Numerous attempts were made to install Windows 10 (v.1909) with the SSD still attached to HDD0. They all failed, due apparently to a Dell RAID / Windows 10 incompatibility. Various Windows 10 folders were left behind, in both partitions of the SSD).

3. The SSD was then attached to SATA0 (the DVD drive connector) and immediately I got a Windows 10 setup prompt. W10 was successfully installed and activated using the new key W7.

Observations:

With the HD on HDD0 and the SSD on HDD1/2/3:

1. Windows 7 (OEM) boots fine. Boot Manager offers W7 or W10 but W10 will not boot.

With the HD on HDD0 and the SSD on SATA1:

1. Windows 7 Boot Manager offers W7 or W10 but W10 will not boot.
2. To get W10 to boot I have to go into BIOS options and specifically select the SSD.
3. With SSD selected at BIOS, W10 will now boot but it cannot see the HD.
4. The W10 Boot Manager contains only the W10 boot loader. The W7 one cannot be added because the HD is not visible.

I am out of ideas here and some lateral thinking would be really helpful. Could the problem arise from the different methods of installing (the new) Windows 7 and Windows 10? For W7 the SSD was on HDD0 but for Windows 10 it was on SATA1. If so, what would fix it? Any thoughts on that appreciated - thanks.Attachment 263856

For some reason you have recovery partition set as active boot not windows

Try3 said:

I used these instructions to set up Win7-Win10 dual-booting. How to dual boot Windows 10 Technical Preview with Windows 7 - JWStuart {I had previously come across JWStuart in Windows forums and had formed a high regard for his competence} <snip> Both the Win7 & Win10 disks were connected throughout the setup procedure. That is probably where you have gone wrong.
Denis

Thank you, Denis. I hear you about JW Stuart's expertise but AFAICS he installed the second O/S on the same disk, thus issues of compatibility, motherboard slot type and which devices to unplug or leave plugged in will not have arisen.

If you are right, though, and my mistake was to unplug the HD while installing W7 & W10 on the SSD, is there any way to recover from this now without a full reinstall of W10?

- - - Updated - - -

Samuria said:

For some reason you have recovery partition set as active boot not windows

Where should W7 boot from,Samuria? I have not knowingly changed any settings for my main OEM Windows 7 (on the HD) . However, when I added the Windows 10 boot loader, with bcdboot E:\Windows, Windows 7 was at first unable to boot. (It recovered itself in a subsequent reboot.) Is it possible that this changed something? Unfortunately I do not have a screenshot of how things looked before my dual-boot attempts.

At any rate, the main problem seems to be that the Windows 10 (on the SSD) cannot see the hard drive. If it could, bcdboot could probably get things working.

Orcadian said:

With the HD on HDD0 and the SSD on HDD1/2/3:

1. Windows 7 (OEM) boots fine. Boot Manager offers W7 or W10 but W10 will not boot.

In that instance, open a Command Prompt (Admin) or Powershell (Admin) and run:
bcdboot E:\Windows
bcdboot C:\Windows /d /addlast
exit

Change E: drive letter to match whatever drive letter Windows 10 has in Windows 7.

NavyLCDR said:

In that instance, open a Command Prompt (Admin) or Powershell (Admin) and run:
bcdboot E:\Windows
bcdboot C:\Windows /d /addlast
exit

Change E: drive letter to match whatever drive letter Windows 10 has in Windows 7.

I'm not sure I understand, NavyLCDR. Some time ago I did add Windows 10 to the W7 boot menu, with bcdboot E:\ Windows. That worked fine: Windows 7 Boot Manager can see both disks and offers both W7 and W10. The problem is that Windows 10 can see only the SSD - so I cannot use bcdboot to add the other disk, i.e. the HD.

In the future I want to add a second SSD (to hold my data), but unless we can sort out this 'disk visibility' problem, this is going to work: Windows 10 will not be able to see that disk either.

Am I missing something?

I guess the first issue you need to sort out is the UEFI settings for SATA controllers so that the SSD and HDD can both be on "hdd" ports and be recognized. Is there a way to disable raid in UEFI?

NavyLCDR said:

I guess the first issue you need to sort out is the UEFI settings for SATA controllers so that the SSD and HDD can both be on "hdd" ports and be recognized. Is there a way to disable raid in UEFI?

NavyLCDR, Natively the machine is in Legacy boot mode. I have not changed this as I'm not sure what circumstances would require UEFI. This machine was supplied in 2013 with Windows 7. (I have read that UEFI is reqd for W8.) Yes, I can disable the SATA/RAID controller - but when I do that, Windows 7 will not boot. ("No boot device found".)

Incidentally, during bootup there is a screen that says both disks (HD and SSD) are "non-RAID disks". There is a ctrl+I option at this point and I have attached a picture of the screen you reach. There is an option to change from Legacy to UEFI but I have not tried it. Would it be helpful to see the UEFI screen(s)?

You don't disable the SATA/RAID controller itself, you only disable RAID. Is there an option to disable Intel Rapid Storage Technology (IRST) in BIOS settings?