[Windows 10] 0xc1900104,0x800f0922 What to do if Windows Update (feature update) fails with the error "The system reserved partition could not be updated."


Hello!This time with Windows Update0xc1900104,0x800f0922I would like to introduce how to deal with an error.

I think this phenomenon is a slightly rare pattern as an example of failure when executing the function update program (: FU).After all, I've been working on Windows Update for a long time, but I've never encountered such an event.

To be honest, I'm not sure why this happens when I use it normally, but I will introduce it as a trouble case.


When I execute FU from Setup.exe, the following screen "The system reserved partition could not be updated." Is displayed and it fails.

It seems that the same message or error code may be returned even when upgrading or updating with Windows Update.

"The system reserved partition could not be updated" error appears in Windows 10 - Microsoft Support
When upgrading to Windows 10, I get the error "Unable to update system reserved partition" error code 0xc1900104, or error code 0x8000f0922.


Normally, when you install Windows 10, you will have a partition called "System Reserved" of about 100MB in the invisible area of ​​the hard disk.

"System reserved" example

It seems that the cause is that some files are placed in this area and the capacity is being compressed.

As a test, if you look at the contents of the system reserved partition of the computer that occurred ...

The reserved area is being squeezed

It was filled with mysterious files like this.
If you remove this, it looks pretty good!


① Start the command prompt as an administrator

First, launch the command prompt with administrator privileges.
After pressing Windows key + R


And hold down the Shift and Ctrl keys at the same time and press the Enter key.

Then, the following User Account Control screen may appear, so click "Yes".

Click Yes to run as administrator

If it appears in the title bar as C: \ Windows \ system32cmd.exe, it is running as an administrator.

Example command prompt running as administrator

② Start Diskpart and attach a drive letter to the system reserved partition.

In order to view or tamper with the contents of the system reserved partition, you must first attach a drive letter so that you can access it.This time, let's attach it as a "Y" drive for the time being. (If you already have a Y drive, use a different alphabet)

At the command prompt you just started


And press Enter.Then, the beginning of the command prompt will change to "DISKPART".Diskpart is now ready to start.

Then to display the list of partitions

lys vol

And press Enter.

A list of partitions is displayed like this, and some of them have a size of 100MB. (Volume 3 in my case) This is the system reserved partition.

Then, "Volume3Let's add a drive letter "Y" to ""

sel vol 3
assign letter = Y

If you execute the above command and complete it normally, it will be as follows.

Execution example

If you "lis vol" again here, you can see that it is the "Y" drive.

The drive letter has been changed to Y.

This completes the work on Diskpart. "Exit" to return to the command prompt.

When you return to the command prompt, the first line will be the path to the original System32.

③ Delete unnecessary files at the command prompt

Finally, check for unnecessary files and delete unnecessary files.
Basically, you don't need anything other than the EFI folder, but if you accidentally delete it, it may not start, so it's a good idea to make a backup.

First of all


Type to move to the Y drive.

If you can move to Y drive, the first line will be Y:



When you enter, a list of files will be displayed, so let's delete unnecessary files.

As an example, I put a file called "test.dat"

Use the "del" command to delete any unnecessary files found.

del [filename you want to delete] / f

It depends on the situation, but I think there is no choice but to erase them one by one. (If it has the same extension, you may be able to delete it with * .dat etc ...

If you can delete it cleanly, you can make it only the "EFI" folder as shown below.

Cleaned reserved partition

Now if you run the update again, it won't fail with the same error.


This time, I introduced the solution for the case where the reserved partition is compressed and the update of Windows fails.

In my case, the captured image of the BIOS was filled up for some reason, and upon closer examination, I found that the model had such a function.

However, it should be output to the C drive, so it is a mystery why this happened ...

For the time being, I was able to solve it by this method, so I would be grateful if you could refer to it as an example.

I hope it helps you.


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