Windows BSOD Error 0x00000071 — SESSION5_INITIALIZATION_FAILED Fix

What Does This Error Mean?

The 0x00000071 blue screen error means Windows failed to initialize Session 5 during startup. Session 5 is an internal Windows session used for system services before any user logs in. This crash usually means critical Windows system files or the registry are corrupted. It almost always happens at startup — Windows never fully loads. You'll need to repair Windows from a recovery USB drive to fix this.

Affected Models

Windows 10
Windows 11
Windows 8.1
Windows 7

Common Causes

Corrupted Windows registry hive files damaged by an improper shutdown or crash
Critical Windows system files corrupted or missing after a failed update
Malware infection that modified or deleted essential Windows session files
Hard drive failure with bad sectors affecting the area where Windows stores session initialization data
Faulty RAM causing data corruption during the Windows loading process

How to Fix It

Boot from a Windows recovery USB. On another computer, download the Windows 10/11 Media Creation Tool from Microsoft and create a bootable USB. Boot from it on the affected PC by pressing F11 or F12 at startup and selecting the USB.

The key to enter the boot menu varies by manufacturer: F11 on most Lenovo, Dell, and ASUS PCs; F12 on most HP PCs. Try both if you're not sure.
Run Startup Repair first. From the recovery environment, go to Troubleshoot > Advanced options > Startup Repair. Windows automatically scans for and repairs the most common boot and session initialization failures.

Startup Repair may restart the computer multiple times. Wait until it completely finishes before trying other steps.
Try System Restore. Go to Troubleshoot > Advanced options > System Restore and select a restore point from before the crashes started. This rolls back registry and system file changes without affecting your personal files.

System Restore is only available if restore points were created before the issue occurred.
Repair the Windows registry from the command prompt. In the recovery environment, go to Troubleshoot > Advanced options > Command Prompt. Type the following commands to replace a damaged registry hive: cd C:\windows\system32\config copy system system.bak copy C:\windows\system32\config\RegBack\system . Type Y to confirm.

This copies a backup registry hive over the current one. Only do this if Startup Repair failed — and substitute C: with the actual Windows drive letter if different.
Run the Windows Memory Diagnostic to test your RAM. From the recovery Command Prompt, type: mdsched.exe — this schedules a memory test on the next restart. Reboot and let the test run. If errors are found, one of your RAM sticks is faulty and should be replaced.

A RAM test takes 15-30 minutes. If two RAM sticks are installed, try removing one at a time and testing to identify which stick is bad.

When to Call a Professional

This error requires repair from outside Windows using recovery media. If System Restore and SFC don't resolve it, a technician can analyze the crash dump files and run deeper diagnostics. If hardware (RAM or drive) is at fault, a technician can test both and recommend replacements. Always back up your data as soon as possible when you have startup errors.

Frequently Asked Questions

What is Session 5 in Windows?

Windows divides its internal processes into 'sessions.' Session 0 is for core system services that run before any user logs in. Session 5 is an internal system session used for initializing certain security and session management components. If Session 5 fails to start, Windows cannot proceed with loading the user interface or any user sessions. This is why 0x00000071 always appears as a very early startup failure.

Is the 0x00000071 error fixable without reinstalling Windows?

Yes — in many cases, Startup Repair or System Restore fixes the issue without a full reinstall. Registry recovery (restoring backup hive files) also works in many cases. A full reinstall should be a last resort. Even if reinstall is necessary, choosing the 'repair upgrade' option keeps your personal files.

How do I back up my files if Windows won't start?

Boot from a Linux Live USB (like Ubuntu) which you can create for free at ubuntu.com. A Linux Live USB lets you run a full operating system from the USB drive without needing Windows to boot. From Linux, you can browse your Windows drive and copy your files to an external drive. Linux can read Windows NTFS drives natively.