Quick fix: Windows 11 doesn’t have a “Last Known Good Configuration” menu option (removed since Windows 7). The modern equivalent is System Restore: boot from Windows install USB → Repair your computer → Troubleshoot → Advanced options → System Restore. Pick a restore point from before the issue.

You remember Last Known Good Configuration as the boot option that reverts to the registry state from the last successful boot. Microsoft removed this in Windows 7. Windows 11 uses System Restore (snapshots) instead — same concept, different implementation. To use it on a non-booting PC, boot from install USB and access System Restore through recovery.

Symptom: Need to revert Windows 11 to a previous working state (registry, drivers, settings) without losing personal files.
Affects: Windows 11 (and Windows 10).
Fix time: ~30 minutes including reboot.

What causes this

Last Known Good Configuration was a Windows feature (XP/Vista/7) that automatically saved the registry’s ControlSet on every successful boot. The feature was removed because System Restore replaced it with broader functionality. System Restore takes snapshots of: registry, system files, installed apps’ metadata, and drivers. Reverting via System Restore approximates Last Known Good Configuration but is more comprehensive.

System Restore must be enabled for the system drive (default in Windows 11). Snapshots are taken automatically before Windows Updates and driver installs.

Method 1: Run System Restore from booted Windows

When Windows still boots normally.

Open Start menu, search Create a restore point. Click to open System Properties → System Protection tab.
Verify Protection is On for your C: drive. If Off, click Configure → Turn on system protection → set Max Usage to 5–10% of drive size. Click Apply.
Back on System Protection tab, click System Restore.
Click Next. The list shows available restore points: dates, descriptions (e.g., “Windows Update,” “Driver installation”).
Pick a restore point from before the issue started. Click Next.
Click Scan for affected programs — shows what apps will be uninstalled/reinstalled by the restore.
Click Finish. Confirm. PC reboots and applies the restore. Takes 5–20 minutes.
After restart, Windows reports if restore succeeded. Test that the previous issue is resolved.

This is the right path when Windows still boots.

Method 2: Run System Restore from WinRE (PC won’t boot)

For when Windows won’t start normally.

Boot from Windows 11 install USB. (Create one with Media Creation Tool from another PC if needed.)
At the install screen, click Repair your computer.
Choose Troubleshoot → Advanced options → System Restore.
Pick your Windows install (if multiple). Pick a restore point.
Confirm and let it run. PC reboots into normal Windows after restore.
If System Restore from WinRE fails: try Startup Repair (next option in Advanced options). It also examines recent changes and reverts problematic ones.
For automated restore on next boot: from WinRE Command Prompt:
```
rstrui.exe /OFFLINE:C:\Windows=active
```
Opens System Restore UI with offline Windows context.

This is the right path for non-booting PCs.

Method 3: Manual registry rollback (advanced)

For when System Restore isn’t available (disabled, no recent points).

Boot to WinRE Command Prompt.
Navigate to C:\Windows\System32\config\RegBack. This contains older registry hive backups (if Windows kept them; newer Windows builds reduced backup frequency).
If files exist (SYSTEM, SOFTWARE, SAM, SECURITY, DEFAULT): they’re the previous registry snapshots.
Back up current hives: copy C:\Windows\System32\config\SYSTEM C:\Windows\System32\config\SYSTEM.bad. Repeat for others.

Copy backup hives to active location:

copy C:\Windows\System32\config\RegBack\SYSTEM C:\Windows\System32\config\
copy C:\Windows\System32\config\RegBack\SOFTWARE C:\Windows\System32\config\
copy C:\Windows\System32\config\RegBack\SAM C:\Windows\System32\config\
copy C:\Windows\System32\config\RegBack\SECURITY C:\Windows\System32\config\

Reboot. Windows uses the restored registry hives.
Caveat: Windows 10 1803+ disabled automatic RegBack updates. Files may be old (months) or missing. System Restore (Method 1/2) is much more reliable.
For driver-specific revert without registry change: in Safe Mode, use Device Manager → right-click driver → Properties → Driver tab → Roll Back Driver.

This is the last resort. System Restore is preferred whenever available.

How to verify the fix worked

After restore, the issue (driver failure, app crash, BSOD pattern) should be gone.
Open System Properties → System Protection. The restore is recorded in the “Last restore point used” entry.
Personal files are unchanged: documents, photos, downloads all remain. Only Windows-level state reverted.

If none of these work

If System Restore fails or has no points, options. Reset This PC → Keep my files: refreshes Windows while preserving documents. Apps are removed, drivers re-detected. Settings → System → Recovery → Reset this PC. In-place upgrade: from a Windows 11 ISO, run setup.exe and choose “Keep personal files and apps.” Reinstalls Windows over itself preserving everything except the broken state. For specific update reverts: Settings → Windows Update → Update history → Uninstall updates. Remove the most recent KB. Targets the specific update without full restore. For driver-specific issues: Device Manager → Driver tab → Roll Back Driver. Per-driver revert. For registry corruption: sfc /scannow + DISM /Online /Cleanup-Image /RestoreHealth. Repairs core system files.

Bottom line: Last Known Good Configuration is replaced by System Restore in Windows 11. Use System Restore from booted Windows or from WinRE if not booting. Choose a restore point before the issue began.