virtualbox.org

My host is Windows 11, and my guest is ubuntu(64bit)
I/O -APIC and PAE/NX is enabled
Error: Kernel panic - not syncing : Attempted to kill idle task I've searched much, and tried to change the numbers of processors to 2
Then another error occured
Error: MP - BIOS bug : 8254 timer not connected to IO-APIC Though it suggested me disabling the IOAPIC, IO/APIC is essential for more than one proccsors
If I change the number of processors to 1, the kernel panic error would occur again
Log file will be uploaded soon
One more question: Why can't I upload the log file?

Khloe_ruby wrote:Why can't I upload the log file?

You can. Zipped log files can be uploaded using the forum's Upload Attachment tab from first day first post. In fact you were already at the correct spot, where you uploaded your pictures.

Khloe_ruby wrote:I/O -APIC and PAE/NX is enabled

Be sure you put the VM settings back where they were. Or even better, delete this VM and start fresh with a new VM. 2 processors in the VM is good.

Khloe_ruby wrote:Though it suggested me disabling the IOAPIC

Switching IO APIC is often bad for the installed VM OS. FWIW, the error message looks to me like it says to set the VM OS's GRUB boot switch to 'apic=debug' or to 'noapic', not adjusting the Virtualbox settings, which the OS designers would not ostensibly know about.

After resetting or making a new VM, run it, then right-click the guest in the main Virtualbox window's guest list, choose Show Log.

Search the far left tab's log for this text:

Attempting fall back to NEM

If you find it, Hyper-V is enabled. You have two options:

A. Try Virtualbox 6.1.36 and matching Extension Pack.

B. Turn off Hyper-V. See HMR3Init: Attempting fall back to NEM (Hyper-V is active).

Thanks very much!
Since the Hyper-V is not active, I simply installed the extension pack and reboot the computer.
Then it worked now.

Great! Glad you're up and running.