Lubuntu black screen after login virtualbox. After upgrading vbox to 5.

Lubuntu black screen after login virtualbox. VM shows a black screen after login.

Lubuntu black screen after login virtualbox The logon screen looks normal. Hello all, I am having an issue with my Ubuntu 20. The VBoxSVGA does not have a display resolution choice of 2560 × 1600. This usually happens because you have an Nvidia or AMD graphics card, or a laptop with Optimus or switchable/hybrid graphics, and Ubuntu does not have the proprietary drivers In particular, I have very limited terminal access: with Ctrl + Alt + F<anything> or Alt + F<anything> I can login and type commands, but I often can't see what I'm typing and after a short time it stops working. I upgraded VBox to 7. VirtualBox FAQ: Check this before asking questions. Processors used: 1 ---> 2. All I get then is a black screen. Yay! I tried to reinstall the The entire installation process goes well and prompts me to reboot to finish installation. Lastly, most of the time it makes sense to After the upgrade, I get the graphical login screen, but then, after logging in, the screen goes black: I cannot use the keyboard or mouse, and I don't get to see my X / gnome desktop. I have a problem with my Virtual box. After reboot the OS, it will show to login screen for me to enter into the desktop. I haven’t updated the system recently or made any changes that could explain the problem. After the installation of Lubuntu 20. 04 scrambled screen. the default of 16MB) has definitely been known to cause graphics problems including a black screen. 04 blank desktop screen after Virtualbox was installed and updated Ubuntu. I tried installing XUbuntu 22. From your vbox. Hypervisor Issue & Solution. I tried to disable Hardware Virtualization an 3D acelaration but the only thing that changes was the black screen that started to have a white underscore blinking. 1-desktop-amd64. I analysed the Log from VM1 and compared it with log from VM2 but did not find anything suspicious. And for the video As title says i got a black screen after upgrade my ubuntu server from 22. However, when choosing it, the screen froze. 10. 04 machine after the new VirtualBox update. I've had the same problem in the past but the problem has always solved it self after restarting the VM. In the terminal, use cd . g. log, the version of Guest Additions for your Linux Guest is out of date (6. boot; login; 22. 32 r149290 win. VBox Version: VirtualBox+Oracle ExtPack Guest OSses: Linux, Windows 10, Location: Germany. 04 Black screen with Ubuntu Logo after boot. Then I restarted Lubuntu. ubuntu server 22. After logging in, the screen went black. Now when I attempt to access the box, I get a screen that looks like everything is loading properly and then a blank screen with a blinking cursor sans prompt in the top left corner of a black screen. I can access the terminal through Ctrl+Alt+F1. After I tried these changes, my Ubuntu VirtualBox keeps getting stuck on the startup screen. 10 on a VM without any errors. Guest Additions are too old for 3D Acceleration: I just had a black screen issue Created a new machine as Ubuntu 64 Bit, installed Kubuntu 22. Online User Manual: A must read if you want to know what we're talking about. 16, when the Build of Virtual Box is 6. Booting into recovery I Installed Lubuntu 18 on Virtual Box 5. virtualbox; login-screen. After upgrading to 6. 5 Location: Greece. iso file When rebooting into it however, it went to a black screen after about 20-30 seconds of booting. VM shows a black screen after login. I am trying to run ubunutu 20. Tried The Lubuntu virtual machine is running on a VirtualBox (version 6. 04 suddenly can't boot, boots into black screen with blinking underscore cursor. 04. It is possible to disable Hi, I was happily running Ubuntu 18. Playing with screen size often allows me to overcome unresponsive cases. Ubuntu 14. Running VBox on Windows 7 Pro with Ubuntu client. 04 on Hyper-V and it installs fine but after installation and reboot, the screen goes black with a flashing screen. 04 VirtualBox black screen I tried all the options. 04; virtualbox; login-screen; Share. 2. I tried to expand my disk (copied the original disk and tried to change a few things to no avail), but now I'm getting a black screen on boot. I could tell that an old version of Virtualbox Guest Additions had been installed as part of the install. 04 stuck on Black screen with Ubuntu Logo after boot. This symptom is true with either Wayland or X11. After performing fresh installs of Ubuntu 24. At the Password: prompt type your user password and press Enter. 0 - 5. If I login in then it's like I'm in a huge terminal because I can run command in. GRUB_CMDLINE_LINUX_DEFAULT="quiet This video shows you the reason and solution of black screen after login in ubuntu virtual machine. I adjusted the VTD size and now I can't get past the black screen after boot. 04 is stopped at a black screen open a text-only console by using the keyboard shortcut Ctrl+Alt+F3. Follow answered Apr 25, 2020 at 16:36. If I change the size of screen at this time, the screen goes all black. Sometimes lack of enough space causes this problem For this, you can press Alr+Ctrl+f2 on the login screen to open a new terminal enter the username and password, Black screen after logging in, after upgrading to 20. I have been using a Lubuntu VM (20. Ask Question Asked 6 years, 6 months ago. 15 works , while 5. 04 machine. Only the VMSVGA adapter So coming to the problem, Ubuntu freezes right after I enter my login password, desktop gui loads and I cannot click anything anymore and my keyboard is not responsive. After updating KDE Neon there comes after booting up only a blackscreen, no Login Screen. I had also used VirtualBox before on a laptop, it worked perfectly. Initial desktop login worked fine. Things I have tried. I have tried to send a CTRL-ALT-F1 signal to get a console, but that got no response. 04 in VirtualBox, the screen was black in fullscreen mode. So, my solution: If not possible, close the Virtualbox window for the VM with the Power Off option set. 0 r118431 system worked but after upgrading Guest Additions i was unable to exit login screen. 0 today. nvidia-340 driver on Ubuntu 20. (Doesn’t seem perfectly black though, it looks like the black with a tiny bit of red used in some Ubuntu screens). So, since all VMs had previously worked and now Hello, I'm running Lubuntu 21. I installed all updates in July and rebooted. But after the initial apt update / apt upgrade and reboot, subsequent login sends me straight to a black screen. After I updated I cannot get Ubuntu to load past the spinning starting screen (Manjaro also fails to load). Either Ubuntu didn't respond or the Virtualbox host key no longer defaults to the CTRL-ALT sequence. 3k 11 11 gold badges 58 58 silver badges 95 95 bronze badges. After a long time, I tried ACPI shutdown and re-started the machine. to go one layer up, then sudo . 2 freezes after login. Right-click the VM in the main Virtualbox window's VM list, choose Show Log. Things I changed: Base memory: 1468Mb ---> 2048Mb. I This happens to me today after upgrade VBox to 5. Now my Ubuntu VM is stuck on the loading black screen with a white underscore. Ubuntu Linux 20. Post by scottgus1 » 30. C:\Program Files\Oracle\VirtualBox>VBoxManage. Installing Nvidia graphics driver in Ubuntu 20. So I wanted to fix it and installed the following in guest OS (20. Discussions related to using VirtualBox on Mac OS X hosts. 18 you should More on the blog: https://bit. 3. Dec 2014, 19:38 VBox Version: VirtualBox+Oracle ExtPack Guest OSses: Win(*>98), Linux*, OSX>10. I faced a problem running KDE Neon as a Guest on a Linux Mint Host. My physical system is Ubuntu 18. 10 in virtualbox. See if there is any In Lubuntu, which worked before, I enter my password, and then it goes black with no message. Hot Network Questions On a multi-lane road with lanes too narrow to share, why adopt the secondary position? “之” 和 "止" 是同一个字吗？ Same problem here on several stations with Ubuntu 24. Add custom resolution in ubuntu vm : https://youtu. 04 to 22. The preview of the virtual machine program displays the same screen. The Overflow Blog Our next phase—Q&A was just the beginning I had the same problem and using following this steps, I was able to resolving it: First open a console on tty2 by pressing Ctrl + Alt + F2 and login to your account. Ubuntu Login screen blank and unresponsive. Press CTRL-ALT-F3 to trigger the CLI, and, once logged in, type:. Re: Ubuntu 20. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab. If you try logging in and you just see a black screen, or Ubuntu brings you back to the login screen, you're experiencing a login loop. 00:00:07. I'm a new Arch user, and after initial installation of plasma-desktop and sddm, I'm unable to get past the login screen with Arch Linux installed as a guest VM in VirtualBox. The mouse and keyboard are unresponsive within the VM. after rebooting the login screen is at 800x600 (or so) resolution. Usually I used this solution in this case before, but it doesn't work now: Disk is full and now I can't boot into Ubuntu; Also in live USB mode I tried to mount it and chroot there, cleaned and uninstalled some apps. That askubuntu post described a process of increasing memory (I thought perhaps that was the problem) but I increased the memory, following the steps up until it told me to open the guest machine and do work within it, but the guest machine still does not display the login page after the ubuntu logo. In the "Logs" subfolder, zip the VM's "vbox. Ivan Didn't begin after upgrading, but suddenly I also got a black screen after logging in. ctrl alt f1 f2 f3 not responding, send shutdown signal no response, but power off does power it off. Post by In this video, I'll show you how to make Ubuntu 22. 2 cannot login after How to solve black screen in ubuntu os virtualbox is shown I have been using a Lubuntu VM (20. now my Ubuntu 20. File managers still show 0 I also tried to downgrade virtualBox, but it didn't work. 04 LTS Desktop full screen and also fix the black screen when the display resolution is set to the highest Sometimes after an upgrade, your system might not bring you to the desktop after logging in. I enter my login credentials without problems, but after clicking on the login button, a black screen appears. 15. 04: 0 Ubuntu 20. 04 on my host machine. After loading, the Ubuntu screen displays a partial login page only including an Ubuntu logo below, but none of the other elements. But don’t worry! In this guide, we’ll go through simple fixes for different situations so you can get your Ubuntu working again without any hassle. 04 black screen after succesful login on Virtual Box. (Configure your host OS to show all extensions I also encountered the black screen with my new installation, and it was a relatively easy fix. Ubuntu 16. The whole screen is black. 10. Lubuntu login menu displayed, but I have been using a Lubuntu VM (20. I appreciate any help. I created new VM for the latest Linux Mint 19. Howto: Install Linux Guest Additions Howto: Use Shared Folders on Linux Guest See the Tutorials and FAQ section at the top of the Forum for more guides. After going through and updating both VirtualBox and Ubuntu, I'm still stuck on the black screen. 0. VM2 was working fine but it stopped working and i think this happen after win10 update,at least this is i think an event that might trigger this. 04 and 24. 0. until I decided to try to up its performance by changing a couple of settings. Every time I upgrade the kernel ( sudo apt-get update But this might not be the problem. I was able to watch F1 output until it gets to: Starting Hostname Service tmp-sanity\x2dmount After which the black screen starts. Improve this question. It would be different if you increased the graphics RAM, as setting that too low (e. 04 (64 bit) in a VirtualBox VM (Windows 10 being the host), and today I decided to upgrade to 20. You have VirtualBox 6. I haven't narrowed it Try 2GB and start the VM right after you log in on the host, so Virtualbox gets first pick at free RAM. Video memory: 16Mb ---> 18 Mb. Right-click the VM in the main Virtualbox window's VM list, choose Show in Explorer/Finder/File Manager. As per your experience, the VM worked when running the old version of "guest additions I try to reinstall the OS on virtualbox by default setting. 2. 04 - 16. Same here, two different XP guests (Disk2VHD converted system drives) on two different host systems, both get a small, XP loading screen -sized black screen after installing guest additions (in safe mode). After login the screen size stayed small and turned black (also I Installed Lubuntu 18 on Virtual Box 5. Another handy trick: At the command prompt, press and hold the spacebar until the cursor wraps around into the next line, then you can see the commands you type. We need to see a complete VBox. 23 posts 1; 2; Next; UMDinfo Posts: 10 Joined: 15. Then click Add, go to C:\Program Files\Oracle\VirtualBox and select the VBoxGuestAdditions. Hot Network Questions Please help me find an old movie where a guy is sent to another planet Can I skip a leg in an inbound flight, Removing that file restored my ability to login without ending up in a black screen. . Share. Tutorial explaining how to resolve the issue with black screen in Ubuntu-based virtual machines after installing VirtualBox Guest Additions, including 3D acceleration, X11 and Wayland tweaks, login manager and session tweaks, manual recovery, Guest Additions from repos and ISO, glxinfo utility, and more Although, after using it for a few minutes I started having problems with being unable to open applications and decided to restart the VM. After rebooting, now I have a black screen after login. I arrive at the login screen, as soon as I press enter it does it's little loading thingy and Thanks for reporting back, unfortunately I have doubts whether any of the settings you mention would have had a direct effect. After upgrading vbox to 5. So after an upgrade check, when Ubuntu told me I could upgrade, I decided to do it, and after the upgrade was done and a reboot, I got the login screen. Start the VM from cold-boot (not from a paused or saved state) / Observe problem / Shutdown the VM (force close it if you have to). I had restored a partition from a clonezilla image to this (virtual) system. Moving virtualbox to my other monitor before logging in fixes the issue. This could mean that a hypervisor could be active. 4 doesn't. Top. 1, I get: A black screen instead of the gdm login screen. 860699 VirtualBox VM 6. 1) on Windows 10 and it was working just fine until now. I'm running lubuntu-20. Seem in the login screen is working fine, once I logged into the desktop there is nothing to show in the desktop even the status bar and the menu bar as what I state on my first post. mpack ↳ Building VirtualBox; ↳ Windows Hosts; ↳ Linux Hosts; ↳ Other Hosts; ↳ Windows Guests; ↳ Linux Guests; ↳ Other Guests; Hello, I seem to be getting a black screen after my Ubuntu v20. 04, and it's working fine for one year till I installed the VirtualBox update, and now the virtual machine is just showing a black screen with a cursor at its left end, and it is not proceeding any further when I tried to fix this problem first I used to get automatically redirected to safe mode but when whenever I From where Lubuntu 18. run. Ubuntu, Kali Linux, Windows 10, they all ran properly. It reboots, I get to the login screen with the drums, it looks like the desktop is going to fire up and then the screen goes black and the only thing active is the mouse pointer. Black screen after 18. /VBoxLinuxAdditions. 18 and the Ubuntu VM boot ends up with a black screen. 22. If you are still facing the issue in Virtualbox then Hyper-V(Hypervisor) may be causing it. I believe I've fixed this. 1. The VM however is running just fine, waiting for Ubuntu to spring to life. Any further attempts result in a similar cycle as before. I see a Ubuntu loading screen (“Ubuntu” title with 4 dotes below it) then after a short time, a black screen. 16 and you have an Ubuntu guest configured for VBoxVGA and you have (ancient) 6. 3 which was installed successfully but after reboot the screen was black. After installing the open tools the machine was blank, but I was able to switch to tty2. I have tried looking for solutions online but I can’t seem to find one that Hi all, the issue I ran into is very simple. I have tried several It gets to a screen that is mostly black, but it has a Ubuntu logo at the bottom. Lubuntu login menu displayed, but after login there is only the black screen. If I do nothing for some time and the system is locked, login menu is displayed. No matter of changing or resizing This can happen after login, before login, or even after an update. The problem started after installing Guest Additions 6. The Lubuntu virtual machine is running on a VirtualBox (version 6. After login in, however, the screen becomes black and remain black, while VBox manager preview showing the desktop. 04) and I always install all updates. I have tried looking for solutions online but I can’t seem to find one that I have VirtualBox with two working virtual machines(VM): Windows and Linux Mint. 0 GAs. 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. An Ubuntu machine will be stuck on a "blank" screen after entering the user name and password in the login screen. This seems to be happening for every VM I start on my ubunutu 22. The VBoxVGA has the choice of 2560 × 1600. 10 from 13. 04 boots to purple screen or black screen with blinking cursor Black Screen after login Ubuntu guest on OS 10. I can boot my machine but it gets stuck on a black screen after I’ve logged in. The machine is still running and I can shutdown with ACPI. Basically VM2 is started but guest host can not load the gui,i see just a black screen. After that go to the VM's menu bar and select Devices -> Optical Drivers -> Choose/Create a Disk Image. 10 in Oracle VM on a win 7 PC. It was running fine. 14, I got a small login screen (800x600), while before the login screen had the full screen size. This is however not the case now, it will always give me a blackscreen after I log in. Modified 6 years, 6 months ago. I've been using Ubuntu on VirtualBox (versions 5. I'm using windows 10 and I installed Ubuntu 22. I'd boot into the Guest, in console mode / virtual console, and uninstall them. Ubuntu 18. 01 with Nvidia drivers. I can't do anything from there. Once login is complete I use fullscreen again and it works. 14. Dec 2009, 19:14 The VM OS booted far enough to start Guest Additions, so the Virtualbox 'hardware' is working. Aug 2021, 15:31 Ubuntu is known to go to black-screen when there is not enough disk space available to start the desktop environment. Black/purple screen after you boot Ubuntu for the first time. And after a short while the login screen is restored. Usually I used this solution in this case before, but it doesn't work now: Disk is OK I was able to get to the menu to boot into recovery mode or into an old kernel. 1 upgrade went well without errors, services work as intended i can ssh to server and manage it from there but i got a black screen on my monitor. I foolishly allowed a dev vm to upgrade to ubuntu saucy salamander 13. reboot and shutdown from ssh works perfectly fine. I am working on my ubuntu 20. 16, I had an Ubuntu 24. At the login: prompt type your username and press Enter. The default is VMSVGA, which I am having the problem with. I tried to disable Hardware Acceleration but this not help thus far. But today Lubuntu asked to do an update via the graphic interface (which I allowed). When using VirtualBox with Ubuntu 18. The login screen was OK. After having fullscreen issue even after installing install the Guest Additions I fallowed steps on different forums. ly/3NNM49nBlank screen after start or after resizing the virtual Linux machine. Thx. Turning off hyperv; Increasing RAM; Turning off 3D acceleration mode; ↳ Using VirtualBox; ↳ VirtualBox on Windows Hosts; ↳ VirtualBox on Windows pre-releases; ↳ VirtualBox on Linux Hosts; The odd thing now is that if I attempt to create a new VM via the old ISO, that too now only goes to a black screen with cursor. Having black screen after logging in, probably because of lack of free space in root. Changed Display Resolution in Preferences -> Monitor Settings. You need to do two things if you get a black screen on VirtualBox while booting a guest OS on Windows 11/10. log", and post the zip file, using the forum's Attachments tab. I tried all these steps: Try reopening your virtual machine after this. This happens on real PCs too. If I then resize the window, the desktop appears I'm not sure if this is a bug in virtualbox / guest additions or some sort of conflict with Ubuntu. The login window is getting stuck after you enter the login credentials. I also tried to downgrade virtualBox, but it didn't work. You must turn on Hyper-V and disable the 3D Acceleration. Please help I provided the log as well. virtualbox was working fine but started having this black screen since trying to use docker-compose inside of the vm and accidently shutting down the pc while downloading files. Discussions related to using VirtualBox on Windows hosts. 04; recovery-mode; Share. sudo nano /etc/default/grub Find the line with the variable GRUB_CMDLINE_LINUX_DEFAULT, and add nomodeset to the variables, so it looks like this:. I am trying to connect on my virtual machine, in order to work on Ubuntu 16. Hello Dear Virtualbox Community, i use Virtualbox for a long time now but i would say in troubleshooting im a beginner. I've tried Linux and Windows guest, but nothing changes. xsession-errors this message: guest on upgrading to VirtualBox V5. 04 VM working quite well. You will get some screen shown If not possible, close the Virtualbox window for the VM with the Power Off option set. On a Windows 11 host with VBox 7. 62), and with the VirtualBox Addon Tools installed. The Ubuntu VM doesn't just have a black screen, it seems to be making no attempt to boot at all. Ubuntu on Virtual Box Retina display problem. I hadn't installed them myself. Not able to install Virtual box in Ubuntu. 04 VM gets stuck at a black screen after the Vbox and Ubuntu logo screens. Could be a problem within the VM's OS itself. 04): sudo apt-get install virtualbox-guest-utils virtualbox-guest-x11 Black screen around Virtualbox VM in fullscreen mode (Guest additions installed) 2. ; Save only I have been using a Lubuntu VM (20. If I resize the display using view/Virtual Screen1/{new resolution}, I can login Lubuntu 20. There are no apparent errors. I made a clean installation of Ubuntu 12. After restarting it, the VM would get stuck on a black screen with a still white underscore. After updating the VB Guest Additions, every time I launch my Linux Mint 19 guest it boots up until the login screen and - after authentication - it doesn't show the display, but only a black screen. It has also happened to me that I start Ubuntu and it starts with that black screen with an underscore (or goes to the inital purple screen with the icons at the bottom, then suddenly turns black with a white underscore). It can also appear after GRUB, making it hard to access your system. the "None", then start the machine, it is totally black. I even downloaded and installed a whole new Ubuntu VM, and that couldn't boot at all. be/MN [Solved] Ubuntu 20. Sometimes, you might see a black screen with a cursor, or face issues in VirtualBox or during installation. 14 on Lubuntu. This is happening inside VMWare virtual machines. However, I'm able to fix this issue with either of the following:. I'm running Ubuntu 20. I tried Black Screen after login with multiple montitors connected through docking station. One caused me to have a black screen after login using the command xrandr like so : xrandr --output VGA-1 --mode 1024x768. No matter of I get a blank screen after entering my login password at the ubuntu login screen. iso in VirtualBox (Version 5. Re: Issues with Ubuntu; black screen with white underscore. Code: Select all. scottgus1 Site Moderator Posts: 20945 Joined: 30. Viewed 3k times 2 . The problem I have is that after bootup, the login window is displayed and I log in but then the screen goes totally black. Now, when I start Lubuntu 20. 0 Read the Forum Posting Guide before opening a topic. 1 VM boots up. log, from a complete VM run, where the problem occurs: . It boots just fine but after I log in the screen just goes black and stays black until I shut it off. ; With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log". There are several causes for login loops: Try a right-click on the folder named cert and choose a command like Open in Terminal. BeastOfCaerbannog. 42_Ubuntu r137960). If it helps I'm using Ubuntu 20. Logs attached. Black screen on login on Ubuntu 22. After changing to terminal (ctrl+alt+F1) i saw in . If I choose. Still just a black screen. I tried booting into an old kernel with no success, same black screen. 1. 18). So my Ubuntu VirtualBox was working fine. 04 I have to leave full screen (Ctrl + F) and reduce VirtualBox display windows by dragging it to a lower size for Ubutnu system to boot an activate view on login window. VBox Version: VirtualBox+Oracle ExtPack Guest OSses: Windows, Linux. 1 Randomly after entering the password, the screen goes black with an X, when pressing ctrl+alt+f4, I enter with the user, reboot and it works. The screen is all black and unresponsive. 10 posts Jul 2021, 15:57. I recently had the problem, that my virtual Linu After the initial Ubuntu loading screen, the screen goes completely black. 30. I could get to my graphical desktop after rebooting and selecting an older kernel from the old Ubuntu: so kernel 4. Black screen at normal boot; login loop at terminal boot - after upgrading 20. 16. Follow edited Nov 6, 2022 at 15:58. 04 VirtualBox black screen after login. I looked online for quite a while troubleshooting and here is information that may be important. 04 > 20. Clean install of 22. You do not have the required permissions to view the files attached to this post. 04 on virtualbox. 04 on virtualbox and continously get the black screen. exe showvminfo June21Ubuntu Name: June21Ubuntu Groups: / Guest OS: Ubuntu (64 bit) UUID: 4b81898f-987d-484c-bdda-c8e2d949516e Config Similar problem here. After trying the steps outlined on this response on the thread, I ended up with the lubuntu login screen and don't know how to get out of it. When I rebooted after installation of GA 6. When I try to start a guest OS, it doesn't start and I get a black screen. But sometime this July an update came out that brought with it a very unpleasant issue. 1 upgrade on virtualbox. Ubuntu 20. I'm having some trouble with getting my Ubuntu to work on a VirtualBox VM. Improve this answer. 1) for a year always the newest versions available (15. amd64 (Jan 17 2022 11:29:30) release log I have then installed the virtualbox guest additions on the guest. Thank you! Edit: just a note, I can't post screenshots right now as my account isn't old enough. Re: Black Screen after login Ubuntu guest on OS 10. Enable 3D Acceleration in Display Settings The upgrade went OK, but when I start the virtual image I get a purple screen with no login prompt. 04 stuck on black screen after boot and login. In your Virtualbox virtual machine instance window check if there is a little turtle visible in the bottom right corner. I don't see anything wrong with the Virtualbox side of things in this log. nyuqozv ixpen hsikrr nwwqy meokxr opaz jtgevu gktglm juhqnof ofxww cizpz ztk sib dqsz xdgtun