MBR2GPT Not Working (Disk Layout validation failed for disk 1)

jachas666, you didn't edit your profile with ALL your hardware specs as I request.
System Specs - Fill in at Ten Forums
If you have a look at the link you will understand why I asked.

The main problem on your computer is that the boot sequence of your Legacy - MBR are in the two disks.
Disk D: is active and has the system files
Drive C: has boot loader and the OS
Your computer boots from D: and then transfer the boot sequence to C:
Is your C: drive Legacy or GPT?
On Disk manager, select View (top menu) - Top

Why you don't have the Win 10 Recovery partition?

Please explain how was Win 10 installed. Did it came from Dell or did you installed?

I filled in profile with my specs as you asked. My C: drive is is Legacy which is why I was attempting to convert it to GPT. I installed Windows 10 from a bootable USB drive that I installed. To my knowledge, I installed all Windows files ony my C: drive (SSD). I am not sure why I do not have the Recovery Partition. Here is the picture you requested:

I backed up my C: drive and set it as a primary partition but I can't seem to find a way to shutdown my D: drive. Could you help me with that?

Did you set the C: partition as Active?
You have a laptop. To disconnect the D: drive you must:
- Take the battery off
- Open the HDD back door and take the HDD off.

If you set the C: partition as Active, you will be able to boot from the drive 0 (don't need to take the HDD off)
Let me know if you're able to boot from drive 0. I will give you more instructions afterwords.

I followed all the steps and the error "MBR2GPT Not Working (Disk Layout validation failed for disk 1)" disappeared. Unfortunately, a new error appeared. It states: "Cannot find OS partition(s) for disk 1".

By the way, thank you for continuing to help me with this issue. Hopefully you can help me solve it soon.

Sounds like the computer is booting from disk 1 still. It needs to be booting from disk 0.

NavyLCDR said:

Sounds like the computer is booting from disk 1 still. It needs to be booting from disk 0.

To be able to boot from disk 0, disk 0 must be Active and you must change boot priority on BIOS.

Megahertz said:

To be able to boot from disk 0, disk 0 must be Active and you must change boot priority on BIOS.

In addition, if the C: drive partition on disk 0 does not contain needed boot files, then:
bcdboot C:\Windows /s C: /f BIOS

Thank you guys for helping me, I successfully converted my C: drive to GPT and am booting through UEFI mode.