Windows Bug Check 0x63: SECURITY1_INITIALIZATION_FAILED

Quick Answer

SECURITY1_INITIALIZATION_FAILED (0x00000063) is a Windows stop error, also called a bug check, that indicates a failure during a security-related phase of Windows initialization. Windows may display a blue screen and restart instead of completing startup. Microsoft documents this error as very infrequent.

The code alone does not identify the underlying cause or establish that the computer has been compromised. Begin by recording the complete stop code, checking for recent hardware, driver, or system changes, and attempting Windows Recovery Environment (WinRE) if Windows cannot start. Use available crash dumps and diagnostic evidence to guide advanced repairs rather than assuming a particular component is responsible.

What Does SECURITY1_INITIALIZATION_FAILED Mean?

The bug check value 0x00000063 identifies the Windows stop error SECURITY1_INITIALIZATION_FAILED. It belongs to the Windows kernel bug-check system and is associated with a failure during an early security-related initialization stage.

Because the error is uncommon, general troubleshooting advice cannot establish its exact cause. The full bug-check information, crash dump, Windows version, and recent system changes may be needed to determine what failed.

Symptoms

• A blue screen displays the stop code SECURITY1_INITIALIZATION_FAILED or 0x00000063.
• Windows restarts before reaching the sign-in screen or desktop.
• The computer repeatedly fails during startup.
• A crash dump may be created if Windows is configured and able to save one.

These symptoms are not exclusive to this bug check. Confirm the displayed stop code before following error-specific troubleshooting steps.

Possible Causes

Microsoft identifies the bug check but does not provide a universal end-user fix or establish one cause that applies to every occurrence. The following are investigation areas, not confirmed causes of this specific stop code.

• Recent driver or system changes: A recently installed driver, update, or system component may be relevant if the failure began immediately afterward.
• Damaged Windows components: Corruption may warrant investigation when other evidence points to operating-system file problems.
• Hardware instability: Memory, storage, or other hardware problems may need testing if crashes occur alongside additional hardware-related symptoms.
• Firmware or configuration changes: A recent BIOS/UEFI or system configuration change may be relevant, particularly if startup failures began directly afterward.
• Unresolved kernel-level failure: Crash-dump analysis may be necessary when ordinary recovery options do not resolve the issue.

Do not assume that a security product, malware infection, or a particular Windows file caused the error solely because its name contains the word “SECURITY.”

Before You Begin

• Photograph or write down the complete stop code and any additional error details.
• Disconnect newly added external hardware, such as USB devices and docking stations, where practical. Do not disconnect internal hardware while the computer is powered on.
• If Windows still starts, back up important files before making system changes.
• If device encryption or BitLocker is enabled, locate the recovery key before entering recovery tools. Never share the key with anyone.
• Record any recent Windows updates, driver installations, firmware changes, or hardware upgrades.

How to Fix SECURITY1_INITIALIZATION_FAILED

1. Restart and Disconnect Recently Added Hardware

If the blue screen appeared only once, allow Windows to restart and check whether it starts normally. If the error began after connecting new hardware, shut down the computer and disconnect the newly added external device.

Restart the computer. If Windows starts normally, reconnect devices one at a time to help identify whether a particular device or its driver is associated with the failure.

2. Enter Windows Recovery Environment

If Windows cannot start normally, use the Windows Recovery Environment (WinRE) to access repair options.

1. Turn on the computer and wait for the Windows or manufacturer logo.
2. If startup fails, hold the power button to shut down the device before Windows finishes loading. Repeat this interruption once.
3. Turn on the computer a third time. Automatic Repair may appear.
4. Select Advanced options to open the recovery tools.

If this method does not work, start the computer from compatible Windows installation or recovery media and select the repair option. Menu names can vary by Windows version and device.

For additional access methods, consult Microsoft's Windows Recovery Environment guide.

3. Run Startup Repair

Startup Repair checks for certain problems that prevent Windows from starting and attempts to repair them automatically.

1. Open WinRE.
2. Select Troubleshoot > Advanced options > Startup Repair.
3. Select the Windows installation if prompted and follow the instructions.
4. Restart the computer and check whether Windows starts.

Startup Repair may not resolve this particular bug check because it is designed for common startup problems, not every kernel initialization failure. Review any diagnostic result it provides.

See Microsoft's Startup Repair documentation.

4. Uninstall a Recently Installed Windows Update

If the problem began immediately after a Windows update, removing the relevant recent update may help establish whether the update is associated with the crash.

1. Enter WinRE.
2. Navigate to Troubleshoot > Advanced options > Uninstall Updates.
3. Choose the appropriate available update-removal option.
4. Follow the prompts, restart, and test Windows.

Not every update can be removed. Removing a security update can expose the computer to vulnerabilities, so use this step as a targeted diagnostic measure and reinstall an appropriate supported update when the underlying problem has been addressed.

For details, see Microsoft's guide to uninstalling Windows updates.

5. Start Windows in Safe Mode

Safe Mode starts Windows with a limited set of drivers and services. If the computer starts in Safe Mode but fails during a normal startup, the difference can help narrow the investigation. It does not, by itself, prove that a driver is responsible.

1. Open WinRE and select Troubleshoot > Advanced options > Startup Settings.
2. Select Restart.
3. After the restart, choose the Safe Mode option shown on the screen, usually option 4 or F4.
4. If Windows starts, review recently installed drivers and system changes.

If a specific driver is implicated by the crash evidence or timing of the problem, use Device Manager or the computer manufacturer's official support site to obtain an appropriate driver. Prefer rolling back a recently updated driver when that option is available and the timing supports doing so.

Follow Microsoft's Windows Startup Settings instructions.

6. Use System Restore

If the problem began after a system change and a suitable restore point exists, System Restore can revert system files, registry settings, drivers, and installed programs to an earlier state.

1. Open WinRE and select Troubleshoot > Advanced options > System Restore.
2. Select an available restore point dated before the error began.
3. Review the affected programs and changes, if shown.
4. Complete the restoration and test the computer.

System Restore is not a substitute for backing up important data. Although it is designed not to remove personal files, it can reverse software and configuration changes made after the selected restore point. If no suitable restore point is available, use another recovery method.

7. Repair Windows System Files if Windows Starts

If Windows can start and there is additional evidence of corrupted system components, use Microsoft's built-in Deployment Image Servicing and Management (DISM) and System File Checker (SFC) utilities.

Requirements: Windows must be running, and you must open Command Prompt with administrator privileges. An internet connection may be needed for DISM to obtain repair files through Windows Update.

1. Open Start, search for Command Prompt, right-click it, and select Run as administrator.
2. Run the following command and wait for it to finish.

DISM.exe /Online /Cleanup-Image /RestoreHealth

DISM checks and repairs the online Windows image using available repair sources. Next, run System File Checker:

sfc /scannow

SFC scans protected system files and attempts to repair missing or corrupted files. Review the completion message from each command, restart Windows, and check whether the problem recurs.

These commands are general Windows integrity checks; they are not a confirmed, specific fix for bug check 0x63. If Windows cannot start, do not assume that the commands above will work unchanged from the recovery Command Prompt. The offline Windows installation and repair-source paths may differ.

See Microsoft's DISM and System File Checker guide.

Advanced Troubleshooting for IT Professionals

Examine Crash Dump Files

If the system creates a crash dump, an administrator or qualified technician can analyze it with WinDbg, Microsoft's Windows debugging tool. A dump may help identify the failing initialization stage, relevant kernel components, and additional diagnostic information.

Check whether a dump exists in the configured crash-dump location. Common Windows dump locations include:

• C:\Windows\MEMORY.DMP — a kernel or complete memory dump, depending on the system configuration.
• C:\Windows\Minidump — a directory commonly used for small memory dump files.

These locations are common defaults, not a guarantee that a dump was created or saved there. Dump settings, available disk space, and the nature of the failure can affect dump creation.

When examining a dump, record the bug-check parameters, Windows build, stack trace, and useful module information. Do not treat a module appearing in the stack as definitive proof that it caused the failure. Kernel debugging may be required to establish the actual failure mechanism.

Use the official Microsoft reference for bug check 0x63 alongside the WinDbg debugging documentation.

Check Hardware and Firmware Only When Indicated

If the computer continues to crash after software recovery attempts, investigate hardware stability and recent firmware or configuration changes. Review manufacturer diagnostics, system logs, and other crash evidence before replacing components.

• Run the computer manufacturer's supported hardware diagnostics, including memory or storage tests when appropriate.
• Check for additional stop codes or hardware errors that may point to a common underlying problem.
• Review recent BIOS/UEFI changes against the manufacturer's documentation before changing firmware settings.
• Install firmware updates only when applicable to the exact model and supported by the manufacturer. Ensure stable power and follow the manufacturer's instructions.

How to Verify the Fix

1. Restart Windows normally and confirm that it reaches the sign-in screen and desktop.
2. Repeat the activity that previously triggered the failure, if it can be done safely.
3. Check whether the same stop code recurs.
4. Review any new crash dump or diagnostic report if another blue screen occurs.
5. Document the change that was made and the observed result, especially on business-managed computers.

If Windows starts but the error returns, continue diagnosis using the new evidence instead of repeating the same recovery procedure indefinitely.

What If the Error Continues?

If Startup Repair, update removal, Safe Mode investigation, and an appropriate System Restore attempt do not resolve the problem, consider professional diagnosis before resetting or reinstalling Windows.

Resetting or reinstalling Windows is a more disruptive step and may remove applications, settings, or personal data depending on the selected method. Back up accessible data first, confirm that recovery keys are available, and use compatible Windows installation media. A clean installation can erase data on the selected drive and should not be the first response to an unexplained stop code.

If the computer is managed by an employer or organization, contact the IT administrator before performing recovery operations that could affect managed security settings, encryption, or business data.

Frequently Asked Questions

What is error 0x00000063 in Windows?

It is the bug-check code for SECURITY1_INITIALIZATION_FAILED, an uncommon Windows blue-screen error associated with a failure during a security-related initialization stage.

Does SECURITY1_INITIALIZATION_FAILED mean my computer has a virus?

No. The stop code alone does not establish that malware is present. Investigate the crash evidence and run an appropriate security scan if there are separate indicators of a possible infection.

Can I fix bug check 0x63 without reinstalling Windows?

Possibly. Depending on the underlying problem, restarting, removing recently added hardware, using Startup Repair, uninstalling a recent update, or restoring an earlier system state may help. There is no single confirmed fix for every occurrence.

Will Safe Mode fix SECURITY1_INITIALIZATION_FAILED?

Safe Mode is primarily a diagnostic option. If Windows starts in Safe Mode, you can investigate recent drivers and system changes. Starting successfully in Safe Mode does not guarantee that the underlying issue is resolved.

Can corrupted system files cause this error?

System file corruption is one possible area to investigate when other evidence supports it, but Microsoft does not establish it as the universal cause of bug check 0x63. DISM and SFC can check Windows component and protected system-file integrity when Windows is running.

Where can I find more information about this stop code?

Start with Microsoft's official SECURITY1_INITIALIZATION_FAILED documentation. It describes the bug-check code and notes that the error occurs very infrequently.

Conclusion

SECURITY1_INITIALIZATION_FAILED (0x00000063) is a rare Windows initialization failure that requires evidence-based troubleshooting. Start with basic checks and supported Windows recovery tools, investigate recent changes, and use crash-dump analysis or hardware diagnostics when necessary. Because the stop code does not establish one universal cause, avoid speculative registry edits, security-setting changes, or destructive recovery procedures without a clear diagnostic reason.

Sources

• Microsoft Learn: Bug Check 0x63 — SECURITY1_INITIALIZATION_FAILED
• Microsoft Learn: Windows Bug Check Code Reference
• Microsoft Support: Troubleshooting Windows Unexpected Restarts and Stop Code Errors
• Microsoft Support: Windows Recovery Environment
• Microsoft Support: Startup Repair
• Microsoft Support: Use DISM and System File Checker to Repair Windows