Ubuntu Guest Booting Into Solid Blue Screen (Win10 Host)

[Rick Smith]

I have been using a particular VM instance (called Safe Browsing) for over a year without any problems. This VM instance was getting close to using all of the hard drive space I allocated to it. I made a full clone of Safe Browsing in its current state (without cloning the snapshots) for backup in case I messed something up while resizing the original VM instance; Safe Browsing. I accidentally deleted the snapshots folder for my original VM instance which now obviously won't work. I (stupidly) didn't make sure that the clone worked before I messed with the original VM instance and now I can't get the clone to boot.

I had the original VM instance working fine the same day that the clone didn't boot. I didn't update VirtualBox or any guest additions or Windows 10 in the small time difference between using the original VM instance and the clone. My problems are very very similar to (it won't let me post links) viewtopic.php?f=3&t=81783. Basically, the display shows the loading screen for Ubuntu for a while then briefly a black screen followed by a solid blue screen. The VM is completely non-responsive and each time I have to power-off the VM instead of shutting down. I followed the troubleshooting for that thread without any luck. I upped the VRAM from 12MB to 32MB and I have 3D turned off. I've seen some people in the forums talk about turning off the Hyper Visor but I'm not sure if that is relevant to my problem so I haven't tried that. VBox.log shows that I have guest additions Version 5.1.26 r117224 '5.1.26'. VBox.log also shows: "OS Product: Linux", "OS Release: 4.4.0-93-generic", and "OS Version: #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC 2017". I don't believe I have ever updated the guest OS (I'm not really sure of this). I have attached VBox.log for the clone.

My only real interest in this VM instance are a few files that I don't have saved anywhere else. These files have taken me considerable amounts of time so any amount of time I spend fixing the VM will be worth it. I've seen that it's probably harder to extract files from a VM instead of making it work. It doesn't really make sense to me why the clone on ostensibly the same configuration would not work.

If someone could please give me some idea of what might be wrong I would greatly appreciate it!!

[socratis]

What happens if you start the VM from a bootable Ubuntu ISO with the same version as the one you have installed. Does it boot?

[Rick Smith]

I think I followed what you said but I'm very new to VMs so I'm not entirely certain. Here is a link to the settings of a VM that is a direct clone of the original VM. https://imgur.com/XSGUMqV. Here is the link to to the settings of the VM after I changed it to use a bootable Ubuntu ISO https://i.imgur.com/WxSG327.

Once I started up the VM, Ubuntu loaded and asked me if I'd like to temporarily try out Ubuntu or if I'd like to install Ubuntu https://imgur.com/oheztMD. I chose to temporarily try out Ubuntu and it allowed me to use Ubuntu but not with any of my files. I shutdown the machine and then it asked me to remove the disk and then press enter. I attempted to shutdown again but it didn't respond which made me power-off the VM. The next time I tried to boot that VM, the same blue screen happened.

I tried booting with a Ubuntu ISO again but chose the install option this time. My options are shown in these pictures https://imgur.com/GNhLa0A https://imgur.com/hgJerfY. The only option that wouldn't completely wipe my files is the custom option but I'm totally lost on what I would have to do with that choice.

[socratis]

WAIT!!! I only told you to see if the VM would *boot*, I didn't say to go ahead and install over your existing installation!!! I just wanted to see if there was something fundamentally wrong with the setup, something that I couldn't see from the logs!

I hope you didn't go ahead with the installation...

To make it clear; the easiest way to retrieve the files from the VM is to create a new VM, install Ubuntu on that, and after the installation is done, then attach your old VDI to the new VM as a secondary drive.

BTW, I cannot see all the settings from a screenshot, no way. What you need to do is to right-click on the VM, Show in Explorer. ZIP the ".vbox" file(s) and attach those.

[Rick Smith]

I didn't do the installation! I have been extremely careful not to modify in any way the original VDI clone that I made. I have just been cloning that clone and modifying those ones. I put the original VDI clone in the second SATA port of a freshly installed Ubuntu VM (same version) and boom bam! It booted AND I was easily able to retrieve my old files. I would not have been able to figure it out without your help... you're so god damn awesome!!!! I'm so happy I didn't lose all of my files. HELL YEAH!!

Looking towards the future, is there a list of best practices to make sure that my VMs are going to continue working for a very long time?

Once again, thanks so much! You just saved me so many hours of frustration and repeated work that I can't thank you enough.

[socratis]

OK, disaster adverted!

is there a list of best practices to make sure that my VMs are going to continue working for a very long time?

The question is: what's important, your VMs or the data on them? I'll bet on the second. So, do what you would do in a real system. Back up your data.

You use Ubuntu, so rsync is a quick and dirty, reliable tool for syncing your data with the world outside your VM. Your host or an ext. HD for example. There are plenty of tools out there...

If your VM configuration is also important to you (lots of customization, tools, software), then back up the whole VM as well (or instead). Take a look at the FAQ "Moving a VM" and interpret it as "Backing up a VM".

For a complete VirtualBox backup, you should also back up the "VirtualBox.xml" file. The location of that file depends on the host, see ch. 10.1. Where VirtualBox stores its files of the User Manual.