From BlenderWiki

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.

Windows 2000/XP/Vista/7

When Blender is started on a Microsoft Windows OS, the console is first created as a separate window on the desktop. Then, assuming the right conditions are met, the main Blender application window will appear.

This screenshot shows the two 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 one. If this is the case just use the Windows task bar to click on its icon, which should make the Blender console window visible.
• The Blender console window may be minimized when Blender starts. Again, if this is the case, do as explained above.

GNU/Linux

Under GNU/Linux, Blender has no console window on its own, but it rather uses the terminal from which it was started. This means that if you want to see this console, you must start Blender from a terminal (xterm/gnome-terminal/…).

Most GNU/Linux distributions have Blender as one of their applications you can install from their packaging systems. When Blender is installed in this way, an entry is usually added to the menu system, allowing you to start Blender by selecting from a start menu or clicking an icon (rather than having to open a separate terminal window and start Blender from there). When Blender is started in this way, the location of the Blender “console window” text will depend on how you launched the whole desktop GUI:

• If you logged in via a GUI “display manager” (the most common case nowadays), then all error messages from all GUI apps will be found in your ~/.xsessionerrors file.
• If you logged into a text console and launched the GUI using the startx command (less common nowadays), then all error messages will be displayed on that text console.

This screenshot shows a GNU/Linux terminal from which Blender is started, resulting in Blender outputting its console text to it:

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

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 Blender’s 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’s messages can also originate from many different sources (internally from within the Blender code, externally from Python scripts which Blender executes, and from varying 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 (programmer’s term for building software), it is compiled to expect a particular version of Python, as reported on the Blender console. So this message reports the current version of Python that Blender will use when running.

Checking for installed Python... got it!

Blender can use the Python language in two 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 can be used by Blender (as stated by this message), then Blender will 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 if the version it finds is not usable, then it will use an internal (cut down) version of Python called PyBlender. Even though this internal version of Python is less featured, 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 www.python.org website and download the required version of Python. The Windows version of Python comes with a simple-to-use installation program. On GNU/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 distribution, have your 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 for 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 the request. If this happens, Blender will not be able to carry out the tasks you required of it. 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 install more memory in your system, reduce the amount of detail in your Blender models, or shut down other programs and services/daemons which may be taking up memory that Blender could use.