[SOLVED] Ubuntu VM stuck on black screen with a white underscore, no apparent error

[Mich1010]

Hi,

I have been using my Ubuntu (16.04.3) VM on Windows 10 without any issues for a long time.

Now my Ubuntu VM is stuck on the loading black screen with a white underscore. There are no apparent errors.

I can only think of 3 event that might trigger this:

1) Windows 10 updated
2) I moved the vdi from the C disk to the D disk because I needed to free space on the C disk (I did this properly by detaching, moving and retaching the vdi)
3) I installed Docker desktop

After this I got the vt-x error probably caused by the installation of Docker, which I solved by disabling Hyper-V. I also checked and the virtualization is enabled in the Bios.

I don't get any errors, and the VM seems to boot properly, as I can access the boot options, but then Ubuntu never actually loads and the screen is stuck on a black screen with the white underscore. I have waited a long time (>30mins), but nothing happens, the black screen remains forever.

I attach the VBox.log.

Thanks in advance for any help. Very appreciated.

Mich1010

[scottgus1]

Theoretically, Hyper-V is off:

00:00:02.118289 HM: HMR3Init: VT-x w/ nested paging and unrestricted guest execution hw support
....
00:00:03.234492 HM: Using VT-x implementation 2.0

The guest is apparently able to find your drives:

00:00:01.983015 File system of 'D:\Michel\VB_space\Linux_Ubuntu.vdi' is ntfs
00:00:01.984616 File system of 'D:\Michel\VB_space\VB_data2.vdi' is ntfs
.....
00:00:02.851521 AIOMgr: Endpoint for file 'D:\Michel\VB_space\Linux_Ubuntu.vdi' (flags 000c0723) created successfully
00:00:02.854468 AIOMgr: Endpoint for file 'D:\Michel\VB_space\VB_data2.vdi' (flags 000c0723) created successfully

Extension Pack version should match the Virtualbox version, though it might not always cause a crash:

VirtualBox VM 5.1.26 r117224 win.amd64 (Jul 27 2017 12:32:13) release log
00:00:01.863137 Oracle VM VirtualBox Extension Pack (Version: 5.1.30 r118389; VRDE Module: VBoxVRDP)

You get this repeated many times, right after Virtualbox touches the hard disk, which should be identifying a problem, though what problem it is... :

00:00:05.810320 VMMDev: Guest Log: BIOS: Booting from Hard Disk...
00:00:06.396871 Display::handleDisplayResize: uScreenId=0 pvVRAM=00000000109d0000 w=640 h=480 bpp=32 cbLine=0xA00 flags=0x0
00:00:06.396912 GUI: UIFrameBufferPrivate::NotifyChange: Screen=0, Origin=0x0, Size=640x480, Sending to async-handler
00:00:06.396986 GUI: UIMachineView::sltHandleNotifyChange: Screen=0, Size=640x480
00:00:06.396997 GUI: UIFrameBufferPrivate::handleNotifyChange: Size=640x480
00:00:06.397122 GUI: UIFrameBufferPrivate::performResize: Size=640x480, Directly using source bitmap content

then the log ends.

I don't know how to interpret this or provide a fix, though. It looks like the guest OS is trying to initialize its graphics system and is unable to.

[multiOS]

The Video Ram allocation in the VM appears to be set to 16 MB, which probably isn't helping display.

[fth0]

Since you have plenty of RAM in your host, you should simply provide the maximum of 128 MB VRAM to the guest (even if 18 MB could be enough for a full HD resolution).

Additionally, you declared the Guest OS as Ubuntu (32-bit) with 16 GB of RAM, which seems illogical. Because of this, VirtualBox does not provide an I/O-APIC and other 64-bit capabilities to the guest OS, and if the guest OS is a 64-bit Ubuntu, it may or may not be able to cope with that.

Lastly, most of the time it makes sense to provide 2 vCPUs to a guest OS.

[Mich1010]

Hi,

many thanks to scottgus1, multiOS and fth0 for their help.

I could solve the issue by allocating 128 MB VRAM and by declaring the guest OS as 64-bit instead of 32-bit.

It was my first time posting here, and I am so grateful to this community for helping me so fast. Simply amazing.

Thanks.

[fth0]

I could solve the issue by allocating 128 MB VRAM and by declaring the guest OS as 64-bit instead of 32-bit.

Thank you for your feedback and for marking the topic as solved. Did you make both changes at once? I'm asking because I'd be interested to know which one was the crucial change.

[ojneb2020]

Hi,

many thanks to scottgus1, multiOS and fth0 for their help.

I could solve the issue by allocating 128 MB VRAM and by declaring the guest OS as 64-bit instead of 32-bit.

It was my first time posting here, and I am so grateful to this community for helping me so fast. Simply amazing.

Thanks.

Hi everyone,

I am having the same problem but this solution didn't work for me. I am attaching the log file if someone as an idea of what can be the problem

[IanPrinsCode]

Hi there

I just went to display settings of my VM and unticked Accelerate 3D Graphics.
This solved the exact same issue for me !