I have a very similar problem: I created a virtual machine using VirtualBox 6 and installed Ubuntu 22.04 on it. Recently, I installed VirtualBox 7.0.18 and created a virtual machine with Ubuntu 24.04. This VM installed Ubuntu correctly, but after that would never work properly again.
Sometimes it doesn't boot at all.
Sometimes it prints the error "vmwgfx seems to be running on an unsupported hypervisor".
Sometimes it freezes, while still consuming most of my computer's CPU.
Sometimes it freezes while still consuming very little CPU.
Sometimes it logs me in and gets all the way to showing the Ubuntu desktop, then immediately pops up a window with a memory error, and closes the machine when I click on that pop-up.
VB7 still runs that old Ubuntu 22.04 VM fine, with NO turtle indicating snail mode, so Hyper-V apparently? isn't running, although the 24.04 machine sometimes reports another hypervisor IS running. And I CAN run the 24.04 VM without problem if I insert the Ubuntu 24.04 live CD and boot from that. And I updated to VirtualBox 7.0.20, and still had the same symptoms. So the problem does appear to be with Ubuntu 24.04, not with VirtualBox 7.
I'm very confused by the fact that the 22.04 machine runs at max speed, yet, in another window at the same time, the 24.04 reports another hypervisor is running.
I have a very similar problem: I created a virtual machine using VirtualBox 6 and installed Ubuntu 22.04 on it. Recently, I installed VirtualBox 7.0.18 and created a virtual machine with Ubuntu 24.04. This VM installed Ubuntu correctly, but after that would never work properly again.
Sometimes it doesn't boot at all.
Sometimes it prints the error "vmwgfx seems to be running on an unsupported hypervisor".
Sometimes it freezes, while still consuming most of my computer's CPU.
Sometimes it freezes while still consuming very little CPU.
Sometimes it logs me in and gets all the way to showing the Ubuntu desktop, then immediately pops up a window with a memory error, and closes the machine when I click on that pop-up.
VB7 still runs that old Ubuntu 22.04 VM fine, with NO turtle indicating snail mode, so Hyper-V apparently? isn't running, although the 24.04 machine sometimes reports another hypervisor IS running. And I CAN run the 24.04 VM without problem if I insert the Ubuntu 24.04 live CD and boot from that. And I updated to VirtualBox 7.0.20, and still had the same symptoms. So the problem does appear to be with Ubuntu 24.04, not with VirtualBox 7.
I'm very confused by the fact that the 22.04 machine runs at max speed, yet, in another window at the same time, the 24.04 reports another hypervisor is running.