There are times when a Quickstart VM may get wedged and not boot. Wether it's that lastest update, an experimental tweak, or just plain old "flippin switches" (we've all done it), these things happen.

As with a hardware computer, the solution is to take out the drive, put it in *another* computer, and recover the data that way. The same thing can be done in Virtualbox virtually.

Here's how to recover data from a virtual machine called "Wedged".

1) Create another Virtual Machine called "Rescue". You can import another copy of Quickstart to do this.
2) Shut down "Rescue"
3) In "Rescue", Settings -> add a hard disk -> choose the virtual disk of "Wedged". You may have to go to the settings page of "Wedged" to identify the disk if it isn't obvious.
4) Start "Rescue" and use the Settings -> Administration -> Disk Utility to "mount" the device. An icon should appear for the disk on "Rescue"s desktop.
5) Start a terminal and run e2fsck to check the disk.
quickstart@qs091:~$ sudo e2fsck -f -v /dev/sdb1
6) You should be able to access your files from this disk and make backups.
7) You can try to start the "Wedged" machine - but FIRST shutdown "Rescue" (two computers, one disk. No good will come of this)
8) If that works, rename "Wedged" and remove the drive from "Rescue". Don't "delete all files".

Debugging kernal errors isn't my specialty, so I can't help beyond this, but hopefully this works. Thanks David for the original copy.

quickstart@qs091:~$ sudo e2fsck -f -v /dev/sdb1
e2fsck 1.41.12 (17-May-2010)
/dev/sdb1: recovering journal
Clearing orphaned inode 260625 (uid=114, gid=123, mode=0100600, size=0)
Clearing orphaned inode 260624 (uid=114, gid=123, mode=0100600, size=0)
Clearing orphaned inode 260621 (uid=114, gid=123, mode=0100600, size=0)
Clearing orphaned inode 260620 (uid=114, gid=123, mode=0100600, size=0)
Clearing orphaned inode 260619 (uid=114, gid=123, mode=0100600, size=0)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information

/dev/sdb1: ***** FILE SYSTEM WAS MODIFIED *****

  161023 inodes used (16.07%)
      74 non-contiguous files (0.0%)
     207 non-contiguous directories (0.1%)
         # of inodes with ind/dind/tind blocks: 0/0/0
         Extent depth histogram: 137385/54
  835526 blocks used (20.85%)
       0 bad blocks
       1 large file

  116697 regular files
   17971 directories
      59 character device files
      26 block device files
       0 fifos
     486 links
   26257 symbolic links (23485 fast symbolic links)
       4 sockets
--------
  161500 files