Once you install Windows 7/8/10 on a cleanly formatted disk on your system, it creates a partition on the disk at the beginning of the hard disk. This partition is called System Reserved Partition (SRP). Hence, it uses the balance of unallocated disk space to create a system drive and install your Operating system.

SRP stores boot information for Windows. When the System Reserved Partition is full or any anti-virus software, apps write to it, it can fill up. Hence, when you are upgrading to Windows 7/8/10, you might encounter the error “We couldn’t update system reserved partition” with error code 0xc1900104 or 0x800f0922.

How to resolve the System Reserved Partition error?

Before you try the below method, it is advised that this is risky and can lead to a no-boot situation and data loss.

To update Windows 10, you should free up at least 13 MB of space.

You have to first check whether the SRP is GUID Partition Table (GPT) or Master Boot Record (MBR) partition style.

  • Press Windows button +R to open the Run window.
  • Now type msc and hit Enter.
  • Press and hold or right-click on the hard disk (such as Disk 0), that contains the SRP and select Properties.
  • Select Volumes
  • The Partition Style line will tell you if it is GPT or MBR.
  1. Windows 10 with GPT Partition
  • Press Windows In the search bar, type Command Prompt. In the search results, right-click on Command Prompt and select Run as administrator.
  • In the Command Prompt window, type mountvol y: /s and hit Enter. This adds Y: drive letter to access System Partition.
  • Go to Y drive by tying Y: and hit Enter. Now go to Fonts folder by typing cd EFI\Microsoft\Boot\Fonts.
  • Now type del *.* to delete font files. The system prompts you asking if you are sure. Type Y and hit Enter to continue.
  1. Windows 10 with MBR Partition
  • Press Windows key +R to open the Run window.
  • Now type msc and press Enter.
  • Select partition named System Reserve. Right-click on it.
  • Select Change Drive Letter and Paths.
  • Click Add.
  • Enter Y for the drive letter.
  • Click OK.
  • In Start menu, type Command Prompt. From the search results, right-click on Command Prompt and select Run as administrator.
  • In Command Prompt window, type Y: and hit Enter to go that drive. Go to fonts folder by typing cd Boot\Fonts.
  • Type takedown /d y /r /f . and hit Enter. Note that you have to allow some space and the period after f or the command will not work correctly.
  • To backup permission to the drive, type icacls Y: \* /save %systemdrive%\NTFSp.txt /c /t\ and hit Enter. Make sure all files are shown successful and no single file is failed.
  • Type whoami and hit Enter. Record the username. Type icacls ./grant<username you got from whoami>:F/t and hit Enter. Note that there should not be any space between username and “:F” or command won’t work.
  • Make sure you are still in the Fonts folder (Y:\Boot\Fonts) as shown in Step 9. Now type del*.* to delete font files. If the system prompts you about continuing, type Y and hit Enter.

Restore Permissions

  • Type icacls Y:\ /restore %systemdrive%\NTFSp.txt /c /t and hit Enter.
  • A message might come up stating some files have failed. This is normal as they are deleted before backing up. Just continue.
  • If there are no successful files, then there was an error in processing the command. There should be at least one successful file before continuing.
  • Adjust ACL back to System by typing icacls . /grant system:f /t and hit Enter.
  • Set owner of the drive back to System by typing icacls Y: /setowner “SYSTEM” /t /c and hit Enter.
  • Now go back to Disk Management and Refresh the data to see if the System Partition has the greater percentage of free space. If yes, drive letter can be removed now.
  • Right-click System Reserved Partition.
  • Select Change Drive Letter and Paths.
  • Choose Y:
  • Select Remove.
  • Click OK.

Recover lost or deleted data with Remo Recover software

If you lost any data during the process of increasing size of your System Reserved Partition, you can still recover it using Remo Recover software.

The data recovery tool is capable of restoring data from lost, deleted, formatted and re-formatted partitions as well.

Remo Recover explains in simple steps on how to perform partition recovery on Windows 10 system. You can restore files from deleted/corrupt partitions from a RAID0, RAID1 and RAID5 arrays as well.

File systems supported by the software include FAT16, FAT32, NTFS, NTFS5, and ExFAT. If the hard drive contained bad sectors, Remo Recover creates a disk image of the hard drive bypassing the bad sectors and then recovers data from the image.

All kinds of hard drives, USB drives, memory cards, memory sticks, FireWire drives are supported by the system. The data recovery tool works fine on all versions of Windows and Mac Operating systems.

The user interface is pretty simple. You can restore all your data by following some simple on-screen instructions.