My Windows 10 20H2 guest OS keeps crashing and rebooting after a few minutes of uptime, even when left at idle with no user activity. The amount of uptime before crash varies, from a couple of minutes to maybe 30'.

This is an extract of the VBox.log file with the exception (full log attached):

00:04:04.476177 GIM: HyperV: Guest indicates a fatal condition! P0=0x1e P1=0xffffffff80000002 P2=0xfffff80426ae4793 P3=0xffffbd0cd2c0237a P4=0x7010008004002001
00:04:04.476246 GIMHv: BugCheck 1e {ffffffff80000002, fffff80426ae4793, ffffbd0cd2c0237a, 7010008004002001}
00:04:04.476246 KMODE_EXCEPTION_NOT_HANDLED
00:04:04.476246 P1: ffffffff80000002 - exception code - STATUS_DATATYPE_MISALIGNMENT
00:04:04.476246 P2: fffff80426ae4793 - EIP/RIP
00:04:04.476247 P3: ffffbd0cd2c0237a - Xcpt param #0
00:04:04.476247 P4: 7010008004002001 - Xcpt param #1
00:04:07.226307 AHCI#0: Reset the HBA
00:04:07.226322 VD#0: Cancelling all active requests
00:04:07.226560 AHCI#0: Port 0 reset
00:04:07.227608 VD#0: Cancelling all active requests
00:04:07.367081 VMMDev: vmmDevHeartbeatFlatlinedTimer: Guest seems to be unresponsive. Last heartbeat received 4 seconds ago
00:04:09.277149 VMMDev: Guest Log: VBoxGuest: BugCheck! P0=0x1e P1=0xffffffff80000002 P2=0xfffff80426ae4793 P3=0xffffbd0cd2c0237a P4=0x7010008004002001

The VM's guest OS was freshly installed from Microsoft's ISO. No third party AV software nor drivers installed.

My host setup:

• OS: Ubuntu 20.04.1
• Kernel: tested with 5.8.0-41-generic (Ubuntu) and 5.9.16-050916-generic (mainline)
• System: HP ProBook 650 G8
• CPU: 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz
• VirtualBox: tested with 6.1.16 (Ubuntu's repo) and 6.1.18 r142142 (Oracle's repo)

Conditions that do not cause a crash:

• running the VM in safe mode
• running the VM in a different host with Ubuntu 20.04.1, kernel 5.8, Virtualbox 6.1.18 r142142, CPU AMD Ryzen 9 3900X
• converting the VM's vdi file to qcow2 and running it with KVM

What have been tested without success (VM still crashes):

• running it with a different CPU profile, "i7-6700K" instead of "host"
• uninstalling the VirtualBox Guest Additions
• changing the paravirtualization interface from "Default" to "Legacy"

This issue has been discussed in this forum post: ​https://forums.virtualbox.org/viewtopic.php?f=7&t=101667

Searching the forums for similar problems led to these apparently relevant discussions, all with no solutions nor workarounds:

• ​https://forums.virtualbox.org/viewtopic.php?f=7&t=101280
• ​https://forums.virtualbox.org/viewtopic.php?f=7&t=101353
• ​https://forums.virtualbox.org/viewtopic.php?f=7&t=99789