Memory integrity turns off after restart

[grimacing]

Memory integrity, also known as Hypervisor-protected Code Integrity (HVCI), doesn't persist after subsequent restarts. 

I go to device security --> core isolation details --> click the toggle below memory integrity. Windows checks for incompatible drivers. No incompatible drivers are found and Windows prompts for a restart. I restart the PC and confirm that memory integrity is now enabled. However, memory integrity will be disabled after any further restarts or shutdowns. 

I have tried resetting to factory defaults in the BIOS. The latest BIOS version was flashed. Intel Virtualization Technology (VT) and Intel Virtualization Technology for Directed I/O (VT-d) are enabled in the BIOS (default setting is on). 

Why does memory integrity turn off? How can I ensure that memory integrity stays on? 

Core isolation article by Microsoft - https://support.microsoft.com/en-au/windows/core-isolation-e30ed737-17d8-42f3-a2a9-87521df09b78

System Information: 

OS Name Microsoft Windows 11 Pro

Version 10.0.22621 Build 22621

System Model HP ProDesk 600 G5 SFF

System SKU 7WK35PA#ABG

Processor Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz, 3000 Mhz, 6 Core(s), 6 Logical Processor(s)

BIOS Version/Date HP R07 Ver. 02.17.00, 28/03/2023

BIOS Mode UEFI

Secure Boot State On

Kernel DMA Protection On
Virtualization-based security Running
Virtualization-based security Required Security Properties Base Virtualization Support, Secure Boot, DMA Protection
Virtualization-based security Available Security Properties Base Virtualization Support, Secure Boot, DMA Protection, UEFI Code Readonly, SMM Security Mitigations 1.0, Mode Based Execution Control
Virtualization-based security Services Configured
Virtualization-based security Services Running Hypervisor enforced Code Integrity
Windows Defender Application Control policy Enforced
Windows Defender Application Control user mode policy Off
Device Encryption Support Elevation Required to View
A hypervisor has been detected. Features required for Hyper-V will not be displayed.