= How to create a core dump on Linux =

A core dump is very helpful for helping us tracking down crashes of !VirtualBox. To create a core dump, start !VirtualBox from a command line (e.g. xterm):
{{{
$ ulimit -c unlimited
$ VirtualBox
}}}
or better start the VM directly:
{{{
$ ulimit -c unlimited
$ /usr/lib/virtualbox/VirtualBox -startvm VM_NAME
}}}
Ensure that '''no''' startup script (`~/.bashrc`, `~/.bash_profile`, `~/.profile`) contains an instruction like `ulimit -c 0` as the limit cannot be increased once it was set to zero.

Starting with version 2.0.0, the !VirtualBox processes are started `suid root`. Therefore do
{{{
$ sudo su
$ echo -n 1 > /proc/sys/fs/suid_dumpable
$ exit
}}}
before starting the VM/GUI (note that `sudo echo` will sometimes not work).

When !VirtualBox crashes, a file core.<pid> is created in the current directory. Be aware that core dumps can be very huge. Please compress the file before submitting it to a bug report. Or better don't attach the file to a report. Note that this core dump can contain a memory dump of your guest which can include sensitive information. Send it to frank _dot_ mehnert at sun _dot_ com if the compressed file is smaller than 5MB. Contact me directly otherwise.

= Forcing !VirtualBox to terminate with a core dump =

Sometimes it is required to force a !VirtualBox process to terminate, for example, a VM hangs for some unknown reason. This can be done as follows:
{{{
$ ulimit -c unlimited
$ sudo echo -n 1 > /proc/sys/fs/suid_dumpable
$ /usr/lib/virtualbox/VirtualBox -startvm VM_NAME &
$ pidof VirtualBox
7145
$ kill -4 7145
}}}
Passing the signal number 4 (`SIGILL`) is essential! The same applies to the alternative frontends `VBoxHeadless` and `VBoxSDL`.

= How to create dumps on Mac OS X =
To create a core dump on Mac OS X, start !VirtualBox from a command line:
{{{
$ ulimit -c unlimited
$ VirtualBox
}}}
or better start the VM directly:
{{{
$ ulimit -c unlimited
$ /Applications/VirtualBox.app/Contents/MacOS/VirtualBox -startvm VM_NAME
}}}
Ensure that '''no''' startup script (`~/.bashrc`, `~/.bash_profile`, `~/.profile`) contains an instruction like `ulimit -c 0` as the limit cannot be increased once it was set to zero.

The core files can be found in the /cores folder.

= How to minudumps on Windows =
[http://support.microsoft.com/kb/315263 Please visit Microsoft site for more details about minidumps]
[http://blogs.technet.com/askperf/archive/2007/06/15/capturing-application-crash-dumps.aspx Please visit Microsoft Performance Team blog for more details about Application crash dumps]