Unable to fix error 0xc0000017 on advanced startup due to missing EFI System Partition on Win 10 PC

Snow 40

Hi,

I wanted to upgrade to Windows 11 but I needed to change my BIOS mode from legacy to UEFI. However when I went to advanced startup to follow the instructions on how to change it I got the 0xc0000017 error when I clicked on the command prompt. I basically had the same issue the user had from [this](https://learn.microsoft.com/en-us/answers/questions/2338992/having-trouble-fixing-error-0xc0000017-(advanced-s) post up to the most recent response which still didn't get resolved. I also want to point out that when I typed >bcdedit/delete {badmemory}, I didn't get an error but an access denied message which is below here.

C:\windows\system32>bcdedit/enum all
Windows Boot Manager
--------------------
identifier              {bootmgr}
device                  partition=U:
description             Windows Boot Manager
locale                  en-US
inherit                 {globalsettings}
default                 {current}
resumeobject            {57615d88-34bd-11eb-b184-1803733bf2bc}
displayorder            {current}
toolsdisplayorder       {memdiag}
timeout                 30
Windows Boot Loader
-------------------
identifier              {current}
device                  partition=C:
path                    \windows\system32\winload.exe
description             Windows 10
locale                  en-US
inherit                 {bootloadersettings}
recoverysequence        {57615d8a-34bd-11eb-b184-1803733bf2bc}
displaymessageoverride  CommandPrompt
recoveryenabled         Yes
allowedinmemorysettings 0x15000075
osdevice                partition=C:
systemroot              \windows
resumeobject            {57615d88-34bd-11eb-b184-1803733bf2bc}
nx                      OptIn
bootmenupolicy          Standard
Windows Boot Loader
-------------------
identifier              {57615d8a-34bd-11eb-b184-1803733bf2bc}
device                  ramdisk=[C:]\Recovery\WindowsRE\Winre.wim,{57615d8b-34bd-11eb-b184-1803733bf2bc}
path                    \windows\system32\winload.exe
description             Windows Recovery Environment
locale                  en-us
inherit                 {bootloadersettings}
displaymessage          Recovery
osdevice                ramdisk=[C:]\Recovery\WindowsRE\Winre.wim,{57615d8b-34bd-11eb-b184-1803733bf2bc}
systemroot              \windows
nx                      OptIn
bootmenupolicy          Standard
winpe                   Yes
Resume from Hibernate
---------------------
identifier              {57615d88-34bd-11eb-b184-1803733bf2bc}
device                  partition=C:
path                    \windows\system32\winresume.exe
description             Windows Resume Application
locale                  en-US
inherit                 {resumeloadersettings}
recoverysequence        {57615d8a-34bd-11eb-b184-1803733bf2bc}
recoveryenabled         Yes
allowedinmemorysettings 0x15000075
filedevice              partition=C:
filepath                \hiberfil.sys
bootmenupolicy          Standard
debugoptionenabled      No
Windows Memory Tester
---------------------
identifier              {memdiag}
device                  partition=U:
path                    \boot\memtest.exe
description             Windows Memory Diagnostic
locale                  en-US
inherit                 {globalsettings}
badmemoryaccess         Yes
EMS Settings
------------
identifier              {emssettings}
bootems                 No
Debugger Settings
-----------------
identifier              {dbgsettings}
debugtype               Local
RAM Defects
-----------
identifier              {badmemory}
Global Settings
---------------
identifier              {globalsettings}
inherit                 {dbgsettings}
                        {emssettings}
Boot Loader Settings
--------------------
identifier              {bootloadersettings}
inherit                 {globalsettings}
                        {hypervisorsettings}
Hypervisor Settings
-------------------
identifier              {hypervisorsettings}
hypervisordebugtype     Serial
hypervisordebugport     1
hypervisorbaudrate      115200
Resume Loader Settings
----------------------
identifier              {resumeloadersettings}
inherit                 {globalsettings}
Device options
--------------
identifier              {57615d8b-34bd-11eb-b184-1803733bf2bc}
description             Windows Recovery
ramdisksdidevice        partition=C:
ramdisksdipath          \Recovery\WindowsRE\boot.sdi
C:\windows\system32>bcdedit/delete {badmemory}
This entry cannot be deleted unless the /f switch is specified on the command
line.  Run bcdedit /? for more information.
Access is denied.

Then I followed the rest of the instructions on the post then used the >list partition command, no EFI system partition was located on any of the disks. When I opened Disk Management there isn't a EFI located and I don't know what to do to get the EFI back. Screenshot (394).png

0 comments

Answer accepted by question author

Volume Z 1,765 Volunteer Moderator

Maybe shrinking drive C by 1 MB would work, preferably in disk management? :)

0 comments

Answer accepted by question author

Ramesh 181.6K Volunteer Moderator

Please run msinfo32.exe, and click System Summary. Resize the columns in the right pane to make the entries visible, and post a screenshot.
Open Command Prompt admin and run this command:

mbr2gpt /validate /disk:2 /allowFullOS

Post the output.

Snow 40

Here is the screenshot and output Screenshot (396)

C:\windows\system32>mbr2gpt /validate /disk:2 /allowFullOS
MBR2GPT: Attempting to validate disk 2
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Disk layout validation failed for disk 2

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-11T02:55:30.1433333+00:00
Run:

bcdboot C:\Windows /s U: /f ALL mbr2gpt /validate /disk:2 /allowFullOS

Post the output.

Snow 40

C:\windows\system32>bcdboot C:\Windows /s U: /f ALL
Boot files successfully created.

C:\windows\system32>mbr2gpt /validate /disk:2 /allowFullOS
MBR2GPT: Attempting to validate disk 2
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Disk layout validation failed for disk 2

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-11T04:11:55.4233333+00:00

Please upload the "C:\Windows\Logs\WinREAgent\setupact.log" file.
Snow 40 Reputation points

2026-07-11T04:36:25.5533333+00:00

I can not upload the file, it is saying the log file is more then 3GB.
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-11T04:39:57.78+00:00

Rename or delete the file if possible.

Then, rerun the commands I posted.

Upload the fresh log which will be smaller in size.

Snow 40

I deleted the file and redid the command this is what I got.

C:\windows\system32>C:\Windows\Logs\WinREAgent\setupact.log
'C:\Windows\Logs\WinREAgent\setupact.log' is not recognized as an internal or external command,
operable program or batch file.

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-11T05:39:49.49+00:00
I meant this command:

mbr2gpt /validate /disk:2 /allowFullOS

Did you run it again?

When the command fails, it creates a new setupact.log file. Upload it.
Snow 40 Reputation points

2026-07-11T13:46:45.1566667+00:00

setupact.log
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-11T14:04:45.0566667+00:00
Run this command again:

mbr2gpt /validate /disk:2 /allowFullOS

Upload the fresh log.
Snow 40 Reputation points

2026-07-11T14:34:57.4466667+00:00

setupact.log
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-11T16:03:38.3366667+00:00

ValidateLayout: Last partition too close to the end of the disk. Should end at offset 1000204869120 or below, found at 1000204886016

The above error was encountered.

Please try the method in this video. The fix starts from 9:00 onwards in this video. Be sure to backup the data first because I haven't tried the Align option before.

https://www.youtube.com/watch?v=QiuFC7SQgY4
Snow 40 Reputation points

2026-07-11T23:50:57.56+00:00

Tried to follow instructions from video and used the same disk tool but partition wizard says all partitions are already aligned.
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T02:36:46.0933333+00:00

Can you try the "Convert MBR Disk to GPT Disk" in MiniTool?

Detailed Instructions:

How to Convert MBR Disk to GPT Disk

https://www.partitionwizard.com/help/convert-mbr-disk-to-gpt-disk.html
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T03:17:56.8733333+00:00
Update:

You could try the shrink suggestion first → https://learn.microsoft.com/en-us/answers/a/12865382

because MiniTool free version can't convert the system disk to GPT.

If that doesn't help, try AOMEI Partition Assistant:

https://www.diskpart.com/gpt-mbr/

https://www.youtube.com/watch?v=9TaAnytoafk
Snow 40 Reputation points

2026-07-12T03:53:44.9533333+00:00

I'm confused on shrinking the disk to 1MB, when I entered the amount of space to shrink in MB to be 1 nothing happened so I did the Partition Assistant and that is also not free. I found that Disk Genius actually does it for free, should I do this instead? My only concern when looking at the guide is that I have to convert the disk to GUID partition table and I don't know how to check if the disk supports it. https://www.diskgenius.com/manual/convert-partition-table-style.php
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T04:01:07.05+00:00

Try the mbr2gpt command again.

If the same error occurs, shrink the volume by 250 MB or so.
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T04:03:49.4066667+00:00

when I entered the amount of space to shrink in MB to be 1 nothing happened

Try the mbr2gpt command again.

If the same error occurs, shrink the volume by 250 MB or so.

Snow 40

C:\Windows\system32>mbr2gpt /validate /disk:2 /allowFullOS
MBR2GPT: Attempting to validate disk 2
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
MBR2GPT: Validation completed successfully

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T04:10:43.41+00:00

Ok. You can run the convert command now.

**Important: **After the disk has been converted to GPT, the system must be reconfigured to boot in UEFI mode.

MBR2GPT | Microsoft Learn

Snow 40

C:\Windows\system32>mbr2gpt /convert
ERROR: MBR2GPT can only be used from the Windows Preinstallation Environment. Use /allowFullOS to override.

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T04:36:58.7266667+00:00
Run:

mbr2gpt /convert /disk:2 /allowFullOS
Snow 40 Reputation points

2026-07-12T04:56:53.75+00:00

When I converted to gpt and tried to boot again I got a blue screen saying operating system couldn't be loaded becauae a required file is missing or contains errors with File: \Windows\system32\winload.efi

Error code: 0xc000000e
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T05:24:17.7433333+00:00

Did you check the boot mode to UEFI Only?
Snow 40 Reputation points

2026-07-12T05:30:56.3366667+00:00

There's an option in boot settings for legacy + Uefi or Uefi. I choose the just Uefi option. There is also an option in advanced to set Bios CSM/UEFI Mode which is currently in CSM mode that I have not touched.
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T05:31:53.7266667+00:00

There is also an option in advanced to set Bios CSM/UEFI Mode which is currently in CSM mode that I have not touched.

Set it to UEFI mode.
Snow 40 Reputation points

2026-07-12T05:35:22.0566667+00:00

Changed it and I still have the same blue screen error
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T05:36:35.1733333+00:00
If you have the Windows 10/11 USB setup disk, boot from it and access Windows RE.

In the WinRE Command Prompt, type the following commands:

bcdedit diskpart list disk select disk 2 list part list vol exit

Take photos of the output screen using your phone and share the images here.
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T05:40:29.8833333+00:00

Note: In another case, we fixed the issue by rebuilding the EFI partition: How to fix error code 0xc000000e due to mbr2gpt? - Microsoft Q&A
Snow 40 Reputation points

2026-07-12T05:53:15.41+00:00

Ramesh 181.6K Volunteer Moderator

Run:

diskpart
list  disk
select disk 2
select part 1
format quick fs=fat32 label=EFI
set id=c12a7328-f81f-11d2-ba4b-00a0c93ec93b override
gpt attributes=0x8000000000000000
assign letter=Y
list vol
exit

Post the output.

Snow 40 Reputation points

2026-07-12T06:24:29.0566667+00:00

When trying to format I got this
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T06:25:46.0266667+00:00

It might be due to the spelling mistake.

label vs lable.

label is correct.
Snow 40 Reputation points

2026-07-12T06:35:38.9533333+00:00
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T06:37:17.95+00:00
Run:

bcdboot F:\Windows /s Y: /f UEFI diskpart select disk 2 list part select part 3
Snow 40 Reputation points

2026-07-12T06:41:39.0833333+00:00
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T06:43:17.51+00:00
Run:

del part override select volume Y remove exit
Snow 40 Reputation points

2026-07-12T06:56:14.9133333+00:00
Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T06:58:36.8466667+00:00

Restart the system. Let me know if you can boot into Windows in UEFI mode.
Snow 40 Reputation points

2026-07-12T07:02:07.8566667+00:00

I was able to log in back to windows

4 additional answers

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-12T07:36:19.3+00:00

Never mind I had to press check for updates and now it says I can do it

Ok. The telemetry task has updated the registry. Let me know how the upgrade went.

The BIOS may need to be updated. There is a 2026 BIOS update for your model.
Was this answer helpful?
Snow 40 Reputation points

2026-07-12T22:56:51.06+00:00

I have updated my bios and was able to upgrade to win 11.

Ramesh 181.6K Reputation points Volunteer Moderator

2026-07-13T03:12:48.3333333+00:00

Great. Does WinRE error 0xc0000017 still occur?

If all is resolved, feel free to mark the answer for this thread. Otherwise, please let me know if there's anything else I can help you with.
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

Unable to fix error 0xc0000017 on advanced startup due to missing EFI System Partition on Win 10 PC

4 additional answers

Your answer