The installation failed during the SAFE OS phase with an error during BOOT operation

Hi Guys,

I've seen few people around complaining about this error and others discrediting the actual error saying they never faced this before.

So please allow me to tell you, this is a real error and before making assumptions lets try to understand why this error happens.

I have 3 computers and it happened in 2 of them for different reasons.

I hope posting the solution here will allow someone to fix their problem without clean install.

First case this error happened was:

1st Problem - Secure boot problem.

The upgrade installer cannot authenticate on the current BCD settings saved on BIOS and generates that error immediately after first reboot.

The installation failed during the SAFE OS phase with an error during BOOT operation
0xC1900101-0x20017

Solution: Disable Secure Boot on the BIOS and Execution Prevention setting and Try again.

This worked for my first computer.

2nd Problem - Partition design.

This one I've didn't see mentioned in any on the known internet and its a bit more complicated.

The upgrade installer fails with the error after first reboot, this time for a different reason:

The installation failed during the SAFE OS phase with an error during BOOT operation
0xC1900101-0x20017

This time windows fails upgrading with the above error because the partition layout on the disk you have the system is not correct (I've bare-metal restored 10 times my faulty partition design to test and actually failed with the same error always.

When I corrected it upgraded flawless:




This is how a perfect disk layout should look like, and the error doesn't happen




This is how I fixed my disk layout and was able to do the upgrade perfectly



This is how it was and caused this error every time I tried to upgrade



This is how it is now




If you don't have 1MB (1024kb) before the EFI partition starts the upgrade will fail. This has been verified in UEFI installs only. The OEM partition is not essential.

To fix, please research how to recreate/align the EFI partition using recovery mode, once you delete the broken EFI partition and then you recreate windows will automatically allocate 1024 before the first partition starts.

------------------------------------------------------------------------------------------------------------------------------
Recreate EFI partition

google it, it doesn't allow me to put link here

Rebuild your BCD

You should be able to upgrade without problem


Hope this helps someone

Thanks