Turning off secure boot/fast boot required?

As I get ready to do a clean install of 10074 I am curious about the need to disable secure boot and fast boot options. If I do disable secure boot do I need to enable legacy boot?

I have had limited success with previous installs to a 2nd hard drive and the problems that arose always seem related to dual booting.

In one instance I did a clean install of 10061 and had left secure boot enabled. In order to get dual boot working I had to disable secure boot, and upon rebooting I needed to change it back to secure. I then made Win 8.1 the default boot and then Win 10 would never boot from the menu, it would just take me back to the boot menu and I could boot into Win 8.1.

Additionally I would like to thank all the members who freely share their time and knowledge on the forums. Such a valuable resource!

Hi Gramps,

Yes, disable 'Secure Boot' & 'Fast Boot' than change from UEFI to Legacy

Gramps said:

As I get ready to do a clean install of 10074 I am curious about the need to disable secure boot and fast boot options. If I do disable secure boot do I need to enable legacy boot?

Take a look at this tutorial (the tutorial section is always a good place to start when looking for solutions)
Windows 10 - Dual Boot with Windows 7 or Windows 8 - Windows 10 Forums

Thanks for the responses. The issues I had seemed to be related to having sync on in 8.1 and then 10 would grab that info upon installation using my Microsoft account. In the end I turned off sync in 8.1. I disconnected my primary hard-drive, booted from the 10 USB ISO and installed on the 2nd drive. I did install 10 using only a local account which forces sync off. So far so good, 10074 has been working flawlessly, a couple of minor issues related to Win 10. I just swap drives before booting at this point and both systems are working.

I may try to set up the dual boot but I am happy with the way things are working now. Thanks again!

Good to hear and thanks for posting what you did and how you plan on operating your machine with Win10.

You might want to feed MS the information - there were issue with sync before, so it's not surprising that you ran into some issues.
There more info MS gets on troublesome installations, the better Win10 will be coming out of the gate.

I did submit the info to MS. I did receive another reply from topgundcp but the message isn't here on the forum. It provided this info on how to go ahead and set-up for dual-boot:
It is very
easy to setup dual boot if you want:

1. Turn off secure boot
2. From
Windows 8.1. Make a backup of your BCD from Admin command prompt:
Type:
bcdedit /export backupBCD
3. Shutdown and connect your Windows 10 drive,
reboot to Windows 8.1 (Assuming you have Windows 8.1 connect to first sata port
and 1st in boot priority).
4. Open Disk Management and take a note of the
drive letter of your Windows 10
5. From Admin command prompt: bcdboot
X:\Windows where X is the drive letter of your Windows 10
6. Reboot, you
should have the dual boot menu.

I will give this a try later on today and report back.

I do not change the default UEFI firmware settings, when I installed Windows 10.

I got dual boot working per topgundcp's instructions. So far everything seems fine, although the boot time to the OS select screen is rather slow. I may attempt to turn secure boot back on, I don't believe at this point it would have a negative impact. My only other concern at this point would be what will happen when the next Win 10 update hits. Hoping that if I install it as an update it won't screw with my 8.1 installation. Time will tell! It's been an experience dealing with Win 10 but I am having fun...most days.

genet said:

I do not change the default UEFI firmware settings, when I installed Windows 10.

I never have either and haven't had any problem whatsoever. Dual boot has always been set up for me automatically when installing on a different partition.

I was installing to a 2nd drive. I still think sync was the cause of much of the problem. At this point, secure boot is enabled and dual-boot is working as it should.