Win7 guest locking up on Win10 host

[nicknamehere]

There are several questions regarding guest VM's locking/freezing up but perhaps circumstances for my specific issue is at fault?
I was running Win7 (64bit) with all updates on my desktop and need it for a few older applications so I am trying to run it as a VM under a Win10 host (Windows 10 Pro version 21H2 build 19044.2486). Currently running with 64GB ram and the Win10 OS installed on the NVME drive.

I initially created a VHDX image of the SSD that contains Win7 using the Microsoft app Disk2VHD.
Then the VHDX image was converted to a .vdi file type using the VBoxManage command:
VBoxManage.exe clonemedium disk M:\Windows7.vhdx C:\Windows7.vdi

Next created the VM using the .vdi file in VirtualBox Version 6.1.40 r154048 (Qt5.6.2) which was the most current stable version available at that time.
Allowed 20GB ram
6 cores (out of 12) though have adjusted to 1 trying to resolve this freezing issue
128MB video
3D enabled

Have installed VBoxGuest Additions from current install folder

The issue is that the Win7 VM freezes completely about 2 - 3 minutes after startup.
I can still move the mouse and the host machine is fine but no activity on the VM at all. Even the task manager performance screen is completely stopped/frozen.
I then have to close/reboot the VM only to have it freeze again.
Any help on this issue would be greatly appreciated!

Log file attached.
Please let me know if any other files would be helpful.

[mpack]

00:00:04.143616 NumCPUs <integer> = 0x0000000000000006 (6)
...
00:00:38.875377 CPUM: Physical host cores: 6

Houston, we have a problem. 2 cores is usually enough for guest code. Leave the rest for host code.

[nicknamehere]

Agreed that it shouldn't/doesn't need 6 cores, and as stated above I have set the core limit to 1 and 2 and tried rebooting the VM with each change but the VM continues to lock/freeze within 2-4 minutes after startup.
The VM appears to operate normally for a short while with usable UI and startup applications (Excell, Outlook, task manager), then freezes with no input or activity.
I have attached another log file with cores set to 2 in case that should make any difference.
Thank you for your time! I do appreciate the help on this!

[mpack]

I don't know that it matters, but why do you have a VDI file being loaded from the root folder of your system drive? Keeping user data files in the root folder is frowned upon in polite society...

Anyway, I see the guest locking up, but I have no indication that the VM had a problem. It looks like a guest OS problem. I can see that the funny VDI file is referenced at about the same time (actually seconds apart, but with these timeouts...).

00:04:42.670489 VMMDev: vmmDevHeartbeatFlatlinedTimer: Guest seems to be unresponsive. Last heartbeat received 4 seconds ago
00:04:53.790004 VMMDev: Guest Log: VBoxGuest: BugCheck! P0=0x3b P1=0xc0000096 P2=0xfffff880037a9250 P3=0xfffff8801a743dd0 P4=0x0
00:05:27.881945 Changing the VM state from 'RUNNING' to 'SUSPENDING'
00:05:27.889146 AIOMgr: Endpoint for file 'C:\C_E_drive_(win7)3.vdi' (flags 000c0781) created successfully

Odd that the apparant lockup on the VDI seems to clear as soon as the VM began the process of suspending itself. I hope you are not trying to share a VDI file with another running VM? That definitely will not work. If you want a shareable medium, create a shared folder.

[nicknamehere]

No, not trying to share the VDI. Only one VM running on the host.
The VDI is on the root because this was (hopefully) going to be a quick test of the VDI before making things a little more organized on another local drive (didn't want speed or access to be an issue initially).
If this could be part of the issue, I'll relocate the VDI file and try running again. Will let you know if this changes the operation of the VM.
Not sure what else to try at this point.

Thanks for your time though!

[mpack]

The asterix is not just beside the location of the VDI, I would also like to know something of the content, i.e. what reason you have to believe that the file is good (not corrupted, which includes "not encrypted").

Try disconnecting this VDI entirely for the next test.

[fth0]

(1) 00:04:39.176440 IEM: rdmsr(0x300) -> #GP(0)
(2) 00:04:41.950770 AHCI#0: Reset the HBA
(2) 00:04:41.950788 VD#0: Cancelling all active requests
(3) 00:04:42.670489 VMMDev: vmmDevHeartbeatFlatlinedTimer: Guest seems to be unresponsive. Last heartbeat received 4 seconds ago
(4) 00:04:53.790004 VMMDev: Guest Log: VBoxGuest: BugCheck! P0=0x3b P1=0xc0000096 P2=0xfffff880037a9250 P3=0xfffff8801a743dd0 P4=0x0
(5) 00:05:27.881945 Changing the VM state from 'RUNNING' to 'SUSPENDING'

(1) The guest read MSR_SGXOWNEREPOCH0 (MSR 0x300), which is related to Intels SGX; I don't know if it plays a role here.
(2) A reset on the virtual hard disk SATA controller took place, which happens from time to time, and usually doesn't indicate an issue.
(3) The previous two events took place in a 4 second interval during which one heartbeat was missing (they come every 2 seconds).
(4) A BSOD occurred inside the guest OS, a SYSTEM_SERVICE_EXCEPTION (0x3b) of type STATUS_PRIVILEGED_INSTRUCTION (0xc0000096).
(5) After a BSOD, it often takes ~30 seconds until the reboot is triggered.
All in all, I don't know the cause of the BSOD, but I noticed two non-standard configuration settings:

Do you have a special reason to provide the ICH9 chipset to the VM? If not, you could try if setting System > Motherboard > Chipset to PIIX3 makes a difference.

Do you have a special reason for the RAM pre-allocation?