0x00000003 INVALID_AFFINITY_SET Blue Screen Fix Guide (Windows 10/11)

Understanding the 0x00000003 INVALID_AFFINITY_SET Blue Screen Error

What Does 0x00000003 INVALID_AFFINITY_SET Mean?

The 0x00000003 BSOD indicates that Windows encountered an invalid CPU affinity set during system execution. CPU affinity is a feature that allows the operating system to assign specific processor cores to running processes, which can improve performance in certain scenarios. When this setting becomes corrupted or misconfigured, it triggers the error and forces your PC to stop working abruptly.

This error often appears with the following message on the blue screen:

INVALID_AFFINITY_SET (0x00000003)
A process or thread tried to set an invalid CPU affinity mask.

Common Causes of 0x00000003 INVALID_AFFINITY_SET BSOD

The INVALID_AFFINITY_SET error can occur due to several reasons, including:

• Corrupted or outdated device drivers, particularly those related to hardware acceleration or CPU management.
• Malware or system infections that interfere with process execution.
• Hardware issues, such as faulty RAM or overheating processors.
• Incompatible software or applications that misuse CPU affinity settings.
• Windows updates or system changes that introduce conflicts in core assignments.

Step-by-Step Fixes for 0x00000003 INVALID_AFFINITY_SET

Here are several methods to troubleshoot and fix this BSOD error. Start with the simplest steps first, as they often resolve the issue without further intervention.

1. Restart Your PC in Safe Mode

If your system is unstable due to driver conflicts or malware, booting into Safe Mode can help isolate the problem and prevent further crashes. This mode loads only essential drivers, allowing you to perform diagnostics safely.

• Press the Windows key + I to open Settings.
• Go to Update & Security > Recovery.
• Under Advanced startup, click Restart now.
• After your PC restarts, go to Troubleshoot > Advanced options > Startup Settings.
• Select Safe Mode (4) or Safe Mode with Networking (5) and press F4 or F5 to boot into it.

Once in Safe Mode, proceed with the next steps to identify and fix the issue.

2. Update or Reinstall Problematic Drivers

Outdated or corrupted drivers are a leading cause of BSOD errors like 0x00000003. Updating your drivers can resolve conflicts related to CPU affinity settings.

• Open Device Manager by pressing Windows key + X and selecting it from the menu.
• Expand the categories, such as Display adapters, System devices, or Sound, video, and game controllers.
• Right-click on any device with a yellow exclamation mark (problematic driver) and select Update driver.
• Choose “Search automatically for drivers” if available. If not, proceed to the next step.

• Right-click on the problematic device (e.g., graphics card) and select Uninstall device.
• Check “Delete the driver software for this device” if prompted.
• Restart your PC. Windows will automatically reinstall the driver in most cases.

3. Run System File Checker (SFC) and DISM

Corrupted system files can sometimes trigger BSOD errors. Windows includes built-in tools to scan and repair these files:

• Open Command Prompt as Administrator by searching for “cmd” in the Start menu, right-clicking it, and selecting Run as administrator.
• Type the following command and press Enter:

  sfc /scannow

• Wait for the scan to complete. If errors are found, Windows will attempt to fix them automatically.

• Open Command Prompt as Administrator again.
• Type the following command and press Enter:

  DISM /Online /Cleanup-Image /RestoreHealth

• Wait for the process to finish (this may take several minutes).

These tools will repair corrupted system files that might be causing the BSOD.

4. Check for Malware or System Infections

Malware can interfere with Windows processes, leading to errors like INVALID_AFFINITY_SET. Run a full system scan using Windows Defender or a trusted third-party antivirus tool:

• Open Windows Security by pressing the Windows key + I and selecting it.
• Go to Virus & threat protection > Scan options.
• Select “Full scan” and click Scan now.

If malware is detected, follow the recommended actions to quarantine or remove it. For added security, consider using a dedicated antivirus program like Malwarebytes or Bitdefender.

5. Test Your RAM for Errors

• Press the Windows key + R, type “mdsched” in the Run dialog, and press Enter.
• Select Restart now and check for problems (recommended).
• Follow the on-screen instructions to perform a standard or extended memory test.

If errors are found, replace your RAM modules. If no issues are detected, proceed to the next step.

6. Monitor System Temperature

Overheating processors can lead to BSOD errors. Use third-party tools like HWMonitor or Core Temp to check CPU and GPU temperatures:

• Download and install a temperature monitoring tool (e.g., HWMonitor).
• Run the tool and observe your CPU/GPU temperatures under load.

Ensure proper airflow in your PC case to prevent overheating.

7. Disable CPU Affinity Manually (Advanced Users)

• Press Ctrl + Shift + Esc to open Task Manager.
• Go to the Details tab, right-click on a suspicious process (e.g., a game or application), and select Set affinity.
• Uncheck all CPU cores except one (e.g., Core 0) and click OK.

Test your system after making this change. If the issue resolves, the problematic application may need to be updated or replaced.

8. Perform a Clean Boot to Identify Software Conflicts

A clean boot starts Windows with only essential drivers and services, helping you determine if third-party software is causing conflicts:

• Press the Windows key + R, type “msconfig” in the Run dialog, and press Enter.
• Go to the Services tab, check “Hide all Microsoft services,” then click Disable all.
• Click OK and restart your PC.

After boot

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Last Updated: December 07, 2025
Tested on: Windows 10 (22H2) & Windows 11 (23H2)