Ubuntu running in VirtualBox fails to boot

Question

I have been using VirtualBox to host an Ubuntu VM to work with Python. When starting, I set a size limit of 16 GB, but it ran out, so I tried to increase it. I accidentally made another virtual hard drive replacing the first, but I got it back. However, when I try to boot I get this:

[ 0.958792] [drm:vmw_host_log [vmwgfx]] *ERROR* failed to send log

[ 0.959515] [drm:vmw_host_log [vmwgfx]] *ERROR* failed to send log
/dev/sda5: clean, 190008/458752 files, 1783535/1834240 blocks
[ok] started disk manager
[ok] started network manager wait online
[ok] reached target network is online
Starting tool to automatically collect and submit kernal crash signatures
[ok] started crash report submission daemon
[ok] Created slice user slice of ryan
[ok] Started session 1 of user ryan
Starting user manager for UID 1000...
[ok] started tool to automatically collect and submit kernal crash signatures
[ok] started snappy daemon
Starting wait until snapd is fully seeded
[ok] Started wait until snapd is fully seeded
[ok] started user manager for uid 1000
[ok] Created slice of user clice of gdm
Starting user manager for uid 121
[ok] Started session c1 of user gdm
[ok] Started user manager for uid 121
Stopping user manager for uid 121
[ok] Stopped user manager for UID 1000
[ok] Removed slice user slice of ryan
[ok] stopped user manager for UID 121
[ok] removed slice user of slice gdm
[ok] Created slice user of slice gdm
Starting user manager for uid 121
[ok] Started session c2 of user gdm
[FAILED] Failed to start MySQL Community Server
see 'systemctl status mysql.service' for details
[ok] Started user manager for UID 12

Answer 1

I got the exact same issue. I finally found the answer here:

The same happened to me and the reason was no left space on the disk.

In the case that it could be your problem too, try the following:

During the stucked booting, press Alt+F3 to enter the second terminal, then login. Now you should be in your home folder. Some functionality could be unavailable because of the lack of space. Now try to remove some big files by rm command. You can check the current status of the disc usage by command df -h. After there is enough space on your disk, just enter reboot and the system should boot normally.

from Ubuntu 18.04 hangs on booting with message “started user manager for uid 120” on Asus 1015PX (on Ask Ubuntu).

Just worked for me!  I just had to wait for the command line to stop blinking to enter my login and password (maybe you'll see what I meant).