From BlenderWiki

[edit] The Console Window

The Console Window is an operating system text window that displays messages about Blender operations, status, and internal errors. If Blender crashes on you, it is a good idea to check the Console Window for clues.

[edit] Windows 2000/Xp/Vista

When Blender is started on a Microsoft Windows OS; The Console Window is first created as a separate window on the desktop; Then assuming the right conditions are met, the main Blender Application window should also appear.

This screenshot shows the 2 windows on a Windows Vista OS:

The Blender Console Window may not be visible, some reasons for this are:

• The Blender Application window may be covering the Console Window. If this is the case just use the Windows task bar to click on the Blender Console Window icon, which should make the Blender Console Window visible.

• The Blender Console Window may be minimized/iconifed when Blender starts. If this is the case again, just use the Windows task bar to click on the Blender Console Window icon, which should make the Blender Console Window visible.

[edit] Linux

The Blender Console Window in Linux will generally only be visible on the Desktop if Blender is started from a Linux Terminal/Console Window, as Blender uses the Console Window it is started from to display it's Blender Console output.

Most of the different Linux distributions have Blender as one of their applications you can install from their packaging systems. When Blender is installed in this way an icon is usually also installed into their menu systems; Allowing for Blender to be started by clicking an icon rather than having to open a separate Linux Console/Terminal window and start Blender from there; When Blender is started using an icon rather than being started from a Terminal window, the Blender Console Window text will most likely be hidden on the Terminal that XWindows was started from.

This screenshot shows a Linux Terminal/Console Window from which Blender is started; Resulting in Blender outputting it's Console text to it:

	Closing the Blender Console Window:
	The Blender Console Window must remain open while Blender is executing; If the Blender Console Window is closed then the Blender Application window will also close, and any unsaved Blender work will be lost! The MS DOS command windows and Blender Console Window can look similar, so always make sure that you are closing the correct window (or save your work often in Blender, CtrlW is your friend!)

[edit] Console Window Status & Error Messages

The Blender Console Window can display many different types of Status & Error Messages; These can range in level from Trivial (informing the user what Blender is doing, but having no real impact on Blenders ability to function) to Critical (serious errors which will most likely prevent Blender carrying out a particular task and may even make Blender non-responsive/shutdown completely). The Blender Console Window messages can also originate from many different sources (Internally from within the Blender code, Externally from Python scripts which Blender executes, and from varied types of Plugins, to mention a few).

Here is a list of some of the Blender Console Window messages:

• Compiled with Python version X.Y.

Blender has support for a scripting language called Python; There are many different versions of Python. When Blender software is compiled (programmers term for building software), it can be compiled to expect a particular version of Python at the version reported on the Blender Console Window. So this message reports the current version of Python the current version of Blender will use when running.

• Checking for installed Python... got it!

Blender can use the Python language in 2 different ways depending on how your system is configured. If you have a fully fledged version of Python installed on your system, and it is a version that is able to be used by Blender; Blender will then use the fully fledged version of the Python interpreter. This allows for more features of Python scripts to be used from within Blender.

• Checking for installed Python... No installed Python found.

If Blender cannot find a fully fledged version of Python on your system or the version it finds is not able to be used; Blender will use an Internal (cut down) version of Python called PyBlender. Even though the Internal version of Python is less feature rich, for the most part it is able to carry out most of the tasks required of it by Blender. If you come across scripts which seem not to work correctly, it may well be that they require a full version of Python to be used successfully; It could also be that the script you're trying to run was written for a different version of Blender/Python. If you wish access to the widest range of Python functionality then there are a few ways to obtain it. One way is to go to http://www.Python.org website and download the version you require. The Windows version of Python comes with a simple to use installation program. In Linux you are likely to have Python fully installed already, but if not you can either compile it and install it manually (often not very easy), or if you're using a common Linux distribution, have your Linux packaging system install and setup Python for you (usually much easier).

• malloc returns nil()

When Blender carries out tasks that require extra memory (RAM), it calls a function called malloc (short for memory allocate) which tries to allocate a requested amount of memory to Blender. If however the amount of memory requested by Blender cannot be satisfied malloc will return nil/null/0 to indicate that it failed to carry out a request. If this happens Blender will not be able to carry out the tasks required of it by the user. This will most likely result in Blender shutting down or operating very slowly and non-responsively. If you want to avoid running out of memory; You can either get more memory installed into your system or reduce the amount of detail in your Blender models; Or you can shut down any other programs and services which may be taking up memory that Blender can use.