Fix Slow Boot After Enabling Memory Integrity in Windows 11

Quick fix: Memory Integrity (Core Isolation) loads HVCI before drivers, adding 15–45 seconds to boot when an incompatible driver fails verification and Windows falls back. Find the offending driver in Event Viewer under Code Integrity, update or remove it, and boot time returns to normal.

You toggled on Memory Integrity to harden the kernel, and now the PC takes 90 seconds to boot instead of 25. The slowdown is consistent, not random. Memory Integrity itself doesn’t cost much — it’s a hypervisor-level page-table check — but when a driver fails its signature verification or has an incompatible memory map, Windows retries and fallback-loads it serially, which delays everything that depends on storage and graphics initialization.

What causes the slowdown

Memory Integrity uses Hypervisor-Protected Code Integrity (HVCI). When Windows boots with HVCI on, the hypervisor verifies every kernel-mode driver before loading. A driver signed with a deprecated algorithm, one that maps writable+executable memory pages, or one that was compiled before HVCI was a target — all of these fail verification. Windows then either refuses to load the driver or falls back through a slower compatibility path, and the boot sequence stalls waiting on it.

Common culprits: old printer drivers, virtualization-related drivers (VMware, VirtualBox host networking), kernel-level anti-cheat (older Easy Anti-Cheat builds), and OEM-bundled utilities that haven’t been updated since before HVCI existed.

Method 1: Identify the offending driver in Event Viewer

1. Press Win + X and open Event Viewer.
2. Navigate to Applications and Services Logs → Microsoft → Windows → CodeIntegrity → Operational.
3. Look for events around boot time with source Code Integrity. Common IDs: 3033 (load denied), 3077 (verification failed), 3082 (HVCI-incompatible driver).
4. The event details name the failing driver file (e.g., C:\Windows\System32\drivers\OldPrinter.sys).
5. Note the driver name and its publisher.

If multiple drivers show up, fix one at a time so you can confirm which one was the main delay.

Method 2: Use HVCI Readiness Tool to scan in advance

Microsoft ships a free tool that scans all installed drivers for HVCI compatibility without needing to boot with HVCI on.

1. Download HVCI Compatibility Check Tool (search Microsoft Docs for “hvcireadinesstool”) and extract it.
2. Open an elevated Command Prompt in the extracted folder.
3. Run hvcirdytool.exe scan.
4. Review the output. Each driver gets one of three verdicts: Compatible, Issues found, or Not Compatible.
5. Update or remove every driver in the bottom two categories before re-enabling HVCI.

This is the supported way to prep a system. The tool produces a HTML report you can share with vendors when asking for HVCI-compatible drivers.

Method 3: Remove the offending driver if it has no update

Some drivers will never get an HVCI-compatible update (orphaned vendors, abandonware utilities). Remove them.

1. Press Win + X → Device Manager.
2. Click View → Show hidden devices to reveal non-present devices.
3. Find the device using the offending driver (printer, network adapter, virtualization NIC).
4. Right-click → Uninstall device. Check Delete the driver software for this device if available. Confirm.
5. For drivers without a matching device, open elevated PowerShell and run pnputil /delete-driver oem##.inf /uninstall /force where ## is the driver’s OEM number (find with pnputil /enum-drivers).
6. Reboot and re-check Event Viewer. The Code Integrity errors should be gone.

If the driver belongs to software you still need, install a newer version from the vendor before removing the old one to keep functionality.

How to verify the fix worked

• Reboot. Boot time returns close to the pre-HVCI baseline.
• Open Event Viewer → CodeIntegrity → Operational. No new errors at the recent boot timestamp.
• Open Windows Security → Device security → Core isolation details. Memory integrity shows as On with no warning.
• Run powercfg /sleepstudy and open the HTML report — the boot trace section shows normal kernel-load duration.

If none of these work

If Event Viewer is empty but boot is still slow with HVCI on, the bottleneck may be the firmware itself rather than a driver — older UEFI implementations have a slow path for the early hypervisor handoff. Check for a BIOS/UEFI update from your motherboard or laptop vendor. For workstations with discrete GPUs, an older GPU vBIOS sometimes causes a multi-second delay during HVCI initialization — flash the latest vBIOS if the vendor offers one (NVIDIA and AMD both have official tools). If updating BIOS doesn’t help and you’ve cleared all driver issues, the practical choice is to leave Memory Integrity off — the security benefit isn’t worth a 60-second boot penalty for most users.

Bottom line: HVCI doesn’t slow boot by itself; an incompatible driver does. Use the Readiness Tool to find them in advance, or read Event Viewer after the fact. Once the drivers are clean, boot time returns to baseline with full Memory Integrity protection.