You are trying to update Windows 10 or Upgrade Windows 7/8/8.1 to Windows 10 and Encounter the following Error Message

“We couldn’t update system reserved partition” error installing Windows 10

Symptoms

When upgrading to, or updating, Windows 10, you might encounter the error “We couldn’t update system reserved partition”, error code 0xc1900104, or error code 0x800f0922.

Cause

The System Reserved Partition (SRP) may be full. The System Reserve Partition (SRP) is a small partition on your hard drive that stores boot information for Windows. Some third-party anti-virus and security apps write to the SRP, and can fill it up.

Resolution

Caution: these steps are complicated, and carry some risk. This is best done by advanced users with experience using the command line. If you make an error in entering these commands, you could put your device in a no-boot situation, and possibly lose data you have stored on the device.

To upgrade your device, you'll need to free up 15MB of space on the SRP using the appropriate method below, and then try the upgrade again. If you're updating Windows 10, you need to free up 13MB.

First, determine whether the SRP is GPT or MBR partition style:

  1. Press the Windows key + R. In the Run window that comes up, type diskmgmt.msc and press Enter.
  2. Press-and-hold or right-click on the Disk (such as Disk 0) that contains the SRP, and select Properties.
  3. Choose the Volumes tab.
  4. The Partition Style: line will say either GUID Partition Table (GPT) or Master Boot Record (MBR).

 

Second, choose which method you need:

Method # 1 - Windows 10 with GPT partition

  1. Search for cmd. Press-and-hold or right-click on Command Prompt in the results, and select Run as administrator.
  2. At the command prompt, type mountvol y: /s and then hit Enter. This will add the Y: drive letter to access the System Partition.
  3. Switch to the Y drive by typing Y: and press Enter. Then, navigate to the Fonts folder by typing cd EFI\Microsoft\Boot\Fonts. Once there, type del *.* to delete font files. The system may ask you if you are sure to continue, press Y and then Enter to continue.

 

Method # 2 - Windows 10 with MBR partition

    1. Press the Windows key + R. In the Run window that comes up, typediskmgmt.msc and press Enter.
    2. Select the partition marked System Reserve. Press-and-hold or right-click on it.
    3. Select Change Drive Letter and Paths.
    4. Choose Add.
    5. Enter Y for the drive letter.
    6. Tap or click OK.
    7. From the Start menu, search for cmd. Right-click Command Prompt from the search results, and select Run as administrator.
    8. In the command prompt, type Y: and hit enter to switch to that drive. Then, navigate to the Fonts folder by typing cd Boot\Fonts.
    9. Type the following and press Enter:
      takeown /d y /r /f .Note: You must include the space and the period after the “f”, or the command will not work properly.
    10. Back up the permission to the drive by typing the following and press Enter:icacls Y:\* /save %systemdrive%\NTFSp.txt /c /tNote: Make sure that all files are showed as successful and none as failed.
    11. Type whoami and press Enter, and then record the user name. Type the following command and press Enter:
      icacls . /grant <username you got from whoami>:F /tNote: Do not put a space between the username and ":F", or the command won't work.
    12. Make sure you are still located in Fonts location (Y:\Boot\Fonts) as described in step 8. Then, Type del *.* to delete font files. The system may ask you if you are sure to continue, press Y and then enter to continue.

Restore permissions

    1. Type the following command and press Enter: icacls Y:\ /restore %systemdrive%\NTFSp.txt /c /t
    2. A message may display indicating some files failed while processing – this is normal as these files have been deleted subsequent to backing them up.
    3. If the amount of successful files is none, then the command was executed incorrectly; you must have some files successfully processed before continuing.
    4. Adjust the ACL back to System by typing the following and press Enter: icacls . /grant system:f /t
    5. Set the owner of the drive back to System by typing the following command and pressing Enter: icacls Y: /setowner “SYSTEM” /t /c
    6. Go back to Disk Management and Refresh the data to confirm if the SRP now has a greater percentage of free space. If so, the drive letter can be removed at this point.
    7. Right-click the System Reserved Partition.
    8. Select Change Drive Letter and Paths.
    9. Choose the Y: drive.
    10. Select Remove.
    11. Click OK.

 

Method # 3 - Windows 7 or 8/8.1 with GPT partition

    1. Search for cmd. Press-and-hold or right-click on Command Prompt in the results, and select Run as administrator.
    2. At the command prompt, type mountvol y: /s and then hit Enter. This will add the Y: drive letter in order to access the System Partition.
    3. Type taskkill /im explorer.exe /f and press Enter. Then type explorer.exeand press Enter to restart explorer in Admin mode.
      Note While in this mode, some apps (such as OneNote) will not run.
    4. Open File Explorer and put Y:\EFI\Microsoft\Boot\ in the address bar and press enter.
    5. Select the language folders you want to remove and permanently delete them. They will be indicated by a set of four letters, split with hyphen. For example, en-US means U.S. English; de-DE means German.
    6. Optional: Remove unused font files at Y:\EFI\Microsoft\Boot\Fonts.
    7. After removing the files, reboot the device. This will remove the drive letter, and return explorer.exe to a normal mode.

 

Method # 4 - Windows 7 with MBR partition

This makes a permanent, but small, increase in the available space of the SRP.

Remove language folders

    1. Press the Windows key + R. In the Run window that comes up, type diskmgmt.msc and press Enter.
    2. Select the partition marked System Reserve. Press-and-hold or right-click on it.
    3. Select Change Drive Letter and Paths.
    4. Choose Add.
    5. Enter Y for the drive letter.
    6. Tap or click OK.
    7. From the Start menu, search for cmd. Right-click Command Promptfrom the search results, and select Run as administrator.
    8. In the command prompt, type Y: and hit enter to switch to that drive.
    9. Type the following and press Enter:takeown /d y /r /f .Note You must include the space and the period after the “f”, or the command will not work properly.
    10. Back up the permission to the drive by typing the following and press Enter:icacls Y:\* /save %systemdrive%\NTFSp.txt /c /tNote: Make sure that all files are showed as successful and none as failed.
    11. Type whoami and press Enter, and then record the user name. Type the following command and press Enter:
      icacls . /grant <username you got from whoami>:F /t

      Note:       Do not put a space between the username and ":F", or the command won't work.
    12. Open the SRP drive in File Explorer and access the Boot folder, select the language folders you want to remove and permanently delete them. They will be indicated by a set of four letters, split with hyphen. For example, en-US means U.S. English; de-DE means German.

Truncate the NTFS Log

      1. Check the size of the NTFS Log first. From the Command Prompt, type the following and press Enter:
        chkdsk /L Y:

        • If the size is less than 5000KB, you do not need to truncate the file.
      2. To truncate the file, type the following and press Enter:
        chkdsk /L:5000 /X /F
      3. Go back to the Disk Management window. Tap or click the Actionmenu, and select Refresh. Confirm if the SRP has now a greater percentage of free space. If so, press-and-hold or right-click the System Reserve Partition, and select Change Drive Letter and Paths. Select Y: and choose Remove.

Resize the USN journal, if truncating the NTFS Log doesn’t increase the free space in the SRP.

    1. From the Command Prompt, type the following and press Enter:
      fsutil usn queryjournal Y:

      • This will display the size in hex value. Convert the value to decimal and divide by 1048576, the result will be in MB. (To convert Hex to Decimal: Open the Calculator in Windows, select the View menu, and then choose Programmer. Select Hex, enter the Hex value, and then select Dec)
      • If the journal is 30MB or more, continue with truncating it.
    2. Delete the journal by typing the following command and pressing Enter:
      fsutil usn deletejournal /D /N Y:
    3. Recreate the journal with a new log size value:
      fsutil usn createjournal m=1500 a=1 Y:

Restore permissions

    1. Type the following command and press Enter:icacls Y:\ /restore %systemdrive%\NTFSp.txt /c /t
      • A message may display indicating some files failed while processing – this is normal as these files have been deleted subsequent to backing them up.
      • If the amount of successful files is none, then the command was executed incorrectly; you must have some files successfully processed before continuing
    2. Adjust the ACL back to System by typing the following and press Enter icacls . /grant system:f /t
    3. Set the owner of the drive back to System by typing the following command and pressing Enter: icacls Y: /setowner “SYSTEM” /t /c
    4. Go back to Disk Management and Refresh the data to confirm if the SRP now has a greater percentage of free space. If so, the drive letter can be removed at this point.
    5. Right-click the System Reserved Partition.
    6. Select Change Drive Letter and Paths.
    7. Choose the Y: drive.
    8. Select Remove.
    9. Click OK.

 

Alternatives

If the steps above have you concerned or you are uncomfortable performing them, there is another route you can take which involves purchasing a 3rd party partitioning application (or attempting to use the free Easus Partition Mover provided below) and/or hiring a Technology Service Provider like Aloye Computer Enterprises to assist you with this problem.

Alternative Solution 1: Fix the system reserved partition Using 3rd Party Software

  1. Purchase a 3rd party partition management solution or attempt to use the free download provided above.
  2. Install and configure it.
  3. Execute the steps to use it to make the relevant partition changes as described below.

 Step 1: Locate the drive/partition

  • Which drive/partition do you want to adjust its size? Right-click on it and choose "Resize/Move".

Step 2: Resize the partition

  • You can either shrink the selected partition or extend it.

To shrink the partition, simply use your mouse to drag one of its ends into unallocated space. Expand the "Advanced Settings" list, where you can see the exact disk space for each partition. Once done, click "OK".

Fig. 1 Unallocated space before the drive.

Fig. 2 Unallocated space after the drive.

To extend the partition, make sure that there is unallocated space aside (if there isn't, follow the above steps to create some). In the same way, drag your mouse towards the unallocated space. Click "OK".

Fig. 3 Add unallocated space into the partition

Step 3: Apply changes

  • At this step, you will see the new disk partition information & diagram.

To save changes, click the "Execute Operation" button and then "Apply".

Alternative Solution 2: Hire Experts to Handle the Issue

Since there is a chance the problem could be more complicated than what is addressed in this knowledge article, as there could be additional, pre-existing, and unrelated problems with your computer that may not raise to the level of visibility until you attempt to deal with this issue, you may be best suited to take your computer to local experts in the event physical access to the machine is required in order to resolve other disk or partition issues via special boot-time software that can only be used by someone who has physical access to the computer.

If there are no experts in your geographic region or if you are already an Aloye Computer Enterprises Web Hosting, Dynamics, or Microsoft Platform Customer and wish to mail your computer in for service because you prefer the service experience we provide, you may certainly contact our Business Services Team at 1-844-MR-ALOYE to set up a ship-to-repair service engagement which can range in price from $250 to $600+ depending on a number of factors such as if any pre-existing problems are present among other things.