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  5. RegBack
FolderRisk: Caution

RegBack C:\Windows\System32\config\RegBack

Automatic backup folder for registry hives; since Windows 10 version 1803 it is empty or holds only 0 KB files by default.

Updated on By AltF4 Formation

What it’s for

RegBack used to receive a backup copy of the main hives (SYSTEM, SOFTWARE, SAM, SECURITY, DEFAULT), made by a scheduled task. It let you repair the registry by hand from the Windows Recovery Environment (WinRE) when a boot failed on a damaged hive. On a recent Windows, this folder no longer plays that role.

What it contains

  • Historically, copies of the hives in the parent config folder, refreshed periodically.
  • Since Windows 10 version 1803, automatic backup is off by default to reduce disk footprint: the folder is empty or holds only 0 KB files.
  • The RegIdleBackup scheduled task (in Microsoft\Windows\Registry) still exists. It only makes a copy if the EnablePeriodicBackup value is 1 under HKLM\System\CurrentControlSet\Control\Session Manager\Configuration Manager.

Risks and best practices

  • Do not count on this folder as a backup. Use a system state backup or restore points.
  • If you turn the backup back on, only restore a hive from RegBack from WinRE, and replace the whole consistent set of hives rather than a single one.
  • Do not copy old files over current hives: drivers and services would no longer match.

Useful commands

Fenêtre de terminal
# 0 KB files mean the automatic backup is disabled
Get-ChildItem -Force "$env:windir\System32\config\RegBack" | Select-Object Name, Length, LastWriteTime


# Value that re-enables periodic backup (absent = default behavior)
Get-ItemProperty 'HKLM:\System\CurrentControlSet\Control\Session Manager\Configuration Manager' -Name EnablePeriodicBackup -ErrorAction SilentlyContinue


# Re-enable the backup (as administrator, effective after restart); test with -WhatIf first
New-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Control\Session Manager\Configuration Manager' -Name EnablePeriodicBackup -Value 1 -PropertyType DWord -WhatIf


# Run the backup task on demand
Start-ScheduledTask -TaskPath '\Microsoft\Windows\Registry\' -TaskName RegIdleBackup

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