Windows 10: Change Windows 7 from UEFI to BIOS mode

I have an older computer with Windows 7 installed. I want to transfer that installation to a VirtualBox Virtual Machine. I am using Acronis 2019 Universal Restore in an attempt to restore an image backup of the Win 7 to the VM. The issue I am struggling with at the moment is this: On the hardware computer, the Win 7 OS is booting using the UEFI bootloader. On the Virtualbox I can configure the VM to boot using UEFI, but VB says that it is for "special OSs" and not recommended for Windows 7. I was able to restore the Windows 7 image to the VM, and set the UEFI boot mode but when I try to boot i

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Should I change BIOS Mode to UEFI?

You boot into UEFI mode by disabling CSM mode (or possibly called legacy mode) in your UEFI settings. But, until you prepare your hard drive (or SSD) to boot in UEFI, you likely will fail to boot. To convert your HDD or SSD to boot in UEFI mode you could try this:
Convert Windows 10 from Legacy BIOS to UEFI without Data Loss

But, if you succeed in converting the HDD/SSD to GPT, and you can't change you BIOS to boot in UEFI mode, then again you will fail to boot. So, I would suggest that you really know what you are doing before you undertake changing legacy BIOS (CSM mode) booting to UEFI.

I would suggest running Ubuntu in a Virtual Machine rather than dual booting.

 

Trouble installing windows 7 on RAID in UEFI

As the title says, I'm trying to install Windows on a RAID array in uefi on my Maximus V Formula. When using legacy ROM I can install just fine but I go into CSM and change settings to UEFI only, I can build the array in the UEFI Raid driver (IRST tab in "BIOS") but the array does not show up in the boot menu and when I try to install windows (boot from UEFI DVD drive), The drive does not show up in the Windows install. The next thing I tried was to enable UEFI and legacy oprom in CSM, boot from UEFI DVD drive and install to the RAID array (probably detected by legacy oprom) and it will install. After first reboot, Windows Boot manager will show up as an option in the BIOS boot menu so I set that as first boot device and reboot. I will get to the starting windows screen and then BSOD (too quick to get codes) The last thing I tried was Changing to legacy mode and installing windows to a different drive. once installed, I initialized the Raid array as GPT and rebooted, changed csm back to UEFI only but they RAID array still doesn't show in the boot device list so I repeated the earlier process hoping that It might work because I had initialized as GPT but it still BSODs on starting windows screen. Any help or suggestions would be greatly appreciated

 

Trouble installing windows 7 on RAID in UEFI

I think you were on track with your first try. Windows installer probably needs the RAID driver in order to detect it on install.