Memory Integrity On/Off After Restart? Explained

Memory Integrity (also called Hypervisor-protected Code Integrity, or HVCI) does not permanently turn itself on or off after a restart. If you enable or disable it in Windows Security, the change takes effect only after you restart your PC, and the setting then stays in that state until you change it again. However, a restart can appear to “turn it off” if the feature fails to start due to incompatible drivers, BIOS settings, or a Windows update, and Windows will then show it as off in the Security app.

What Memory Integrity Actually Does

Memory Integrity is a Windows security feature that uses hardware virtualization to run the kernel (the core of Windows) inside a protected container called a Virtualization-Based Security (VBS) environment. This isolation prevents malicious code from injecting itself into high-privilege kernel processes, even if a driver or application is compromised. It is part of the broader “Core Isolation” settings in Windows Security, and it is one of the strongest defenses against rootkits and other low-level malware.

When you turn on Memory Integrity, Windows must verify that every kernel-mode driver on your system is compatible with HVCI. Incompatible drivers can cause the feature to fail to start, which is why Windows may automatically disable it after a restart if it detects a problem. This is not a random toggle; it is a safety mechanism to prevent a blue screen or system instability.

Why It Appears to Turn Off After Restart

There are three common reasons why Memory Integrity shows as off after you restart, even if you previously enabled it:

• Incompatible driver: A kernel driver that does not support HVCI will block the feature from starting. Windows logs this in the System event log and reverts to the disabled state.
• BIOS/Virtualization settings: Memory Integrity requires virtualization extensions (Intel VT-x or AMD-V) and Windows Hypervisor Platform to be active in your BIOS/UEFI. If virtualization is disabled, the feature cannot start.
• Windows Update or policy change: A feature update or a group policy (in managed environments) can reset the setting. In rare cases, a buggy update may temporarily disable it.

If you see it off after a restart, check the Windows Event Viewer under System for events with source “Vulnerable Driver Blocklist” or “Hyper-V-Hypervisor”. The log will often name the offending driver.

How to Enable It Correctly

To turn Memory Integrity on and keep it on, follow these steps:

1. Open Windows Security (search for it in the Start menu).
2. Go to Device Security > Core Isolation.
3. Toggle Memory Integrity to On.
4. Restart your PC when prompted.

If it turns off again, the cause is almost always a driver. You can identify the problematic driver by running msinfo32 and checking the “Kernel Driver” section, or by using the driverquery command in an elevated command prompt. Then update or remove that driver. In some cases, you may need to update your BIOS to enable virtualization explicitly (look for “SVM Mode” on AMD or “VT-x” on Intel).

Common Problems and Fixes

Beyond the restart issue, users often encounter these problems:

• Blue screen after enabling: This is typically a driver crash. Boot into Safe Mode, disable Memory Integrity, update the driver, then re-enable.
• Game or app performance drop: Some games with anti-cheat drivers (e.g., older versions of certain anti-cheat software) are not compatible. You must choose between the game and the security feature.
• Feature grayed out: This means your CPU does not support virtualization or it is disabled in BIOS. Enable virtualization in BIOS and ensure the “Hyper-V” optional feature is not blocked.
• Windows shows “incompatible” even after updating drivers: Some older drivers are simply never updated for HVCI. The only fix is to replace the hardware or keep Memory Integrity off.

Memory Integrity vs. Standard Antivirus

Memory Integrity is not a replacement for antivirus software. It is a complementary layer that protects the kernel from exploits. Standard antivirus scans files and monitors behavior, while Memory Integrity prevents code injection at the highest privilege level. Both are necessary for robust security. Turning off Memory Integrity does not disable Windows Defender, but it does remove a key protection against zero-day kernel exploits.

Should You Keep It On?

For most users, the answer is yes. The performance cost is typically 1-5% in gaming and productivity tasks, and the security benefit is significant. However, if you rely on older hardware or specific drivers that are not compatible, you may need to keep it off. Microsoft’s official stance is that Memory Integrity should be enabled on all supported systems, but they also allow it to be turned off for compatibility reasons.

If you are a gamer using an anti-cheat that conflicts with HVCI, you might see a message from the game asking you to disable it. In that case, weigh the risk: if you play competitive online games, the anti-cheat is critical, but so is kernel protection. Some modern anti-cheat systems (like BattlEye and Easy Anti-Cheat) have been updated to work with HVCI, so check the game’s documentation before disabling.

Frequently Asked Questions

Does Memory Integrity turn off automatically after every restart?

No. If the feature is enabled and all drivers are compatible, it stays on. It only turns off if Windows detects a problem during startup, such as an incompatible driver. You will see a notification in Windows Security if this happens.

How do I know if Memory Integrity is actually running?

Open Windows Security > Device Security > Core Isolation. If the toggle is on, it is running. You can also run msinfo32 and look at “Virtualization-based Security” — it should say “Running” and list “Hypervisor-protected Code Integrity” as a service.

Will enabling Memory Integrity break my older software?

Potentially, yes. Any software that installs a kernel driver without HVCI compatibility will fail to load. This includes some older printer drivers, VPNs, and anti-cheat systems. You may need to update the software or disable Memory Integrity.

Is there a performance cost?

Yes, a small one. Expect a 1-5% reduction in CPU-intensive tasks, especially games. For most users, this is unnoticeable. The security benefit outweighs the minor performance hit in most scenarios.

Can I enable Memory Integrity if my CPU is older than 2015?

It depends. The CPU must support virtualization (VT-x or AMD-V) and SLAT (Second Level Address Translation). Most CPUs from the last decade support these, but you may need to enable them in BIOS. If the option is grayed out in Windows, your CPU likely lacks the required features.

What should I do if Memory Integrity keeps turning off?

Check the Event Viewer for the specific driver that is blocking it. Update or uninstall that driver, then re-enable Memory Integrity. If you cannot find the driver, use the “Driver Verifier” tool (but be cautious — it can cause boot loops if used incorrectly). In managed environments, check group policy settings.

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