Windows not booting up after playing around with registry and UEFI

@Arvind - Hi Arvind, I am unable to install Ubuntu in dual mode. Unfortunately, after editing windows registry and then changing storage controller to AHCI from BIOS, my windows in not booting up.

Can you pls help me out?

Thanks in advance.

Welcome to It’s Foss @alankrit. I’m not an expert, but I would back out your changes. Change your BIOS back to the way it was. If win still does not boot, restore your most recent backup of win. Get your system working again.
Then come back and give us some more details about what you tried and what you think went wrong. I am sure the we can get your system to dual boot.

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Thanks for replying to my comment.

I have restored my windows. Did the following things:

  1. Changed the windows registry of two values as mentioned in the comments.
  2. Changed the storage controller to AHCI from RST
  3. Then tried booting it up on Safe mode.
  4. Tried few random things.

Now the current state of my system is:

  1. Registry values are back to its original state.
  2. In BIOS, the storage controller is AHCI.
  3. Windows 10 is working fine.

Now, I will try to install Ubuntu 20.04 and will share more details with you. Also, whats your take on disabling the secureboot and fast startup mode before installing Ubuntu? This discussion doesn’t talk about it whereas an article on itsfoss says something else. link

I am referring to this discussion

It’s been close to 2 years since I install Linux. I use Linux Mint which works the same as Ubuntu. The biggest problem I ran into was BIOS vs UEFI boot mode. So I would say that the first thing you need to find out is which one is on your current system. A lot of the Linux installs that I tried install in UEFI mode. If Win was BIOS mode, then Win would not boot anymore. You can not mix BIOS & UEFI.
I found this to try on the web.

Is Windows 10 BIOS or UEFI?

On Windows , “System Information” in Start panel and under BIOS Mode, you can find the boot mode. If it says Legacy, your system has BIOS . If it says UEFI , well it’s UEFI .

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I was able to install Ubuntu 20.04 alongside Win10 on dual boot.

Thanks alot for the help. Really appreciate.

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