On a Ubuntu 12.04 machine, whenever I plot something I get an error like:

> 
> /usr/lib/pymodules/python2.7/matplotlib/font\_manager.py:1228:
>  UserWarning: findfont: Could not match :family=Bitstream Vera
>  Sans:style=normal:variant=normal:weight=medium:stretch=normal:size=x-large.
>  Returning /usr/share/matplotlib/mpl-data/fonts/ttf/cmb10.ttf
> 
> 
> 

which I cannot find a solution to online. The following code reproduces the error

```
import pylab as plt
plt.plot(np.random.random((128)))
plt.title("This should be monospaced")
plt.savefig("/tmp/testfig.pdf")

```

and also the matplotlib self test gives this error:

```
python -c "import matplotlib as m ; m.test(verbosity=1)"

```

In [`~/.matplotlib/matplotlibrc`](http://matplotlib.org/users/customizing.html) I have:

```
font.family         : monospace
font.style          : normal
font.variant        : normal
font.weight         : medium
font.stretch        : normal
font.size           : 10.0
font.serif          : Palatino, Bitstream Vera Serif, New Century Schoolbook, Century Schoolbook L, Utopia, ITC Bookman, Bookman, Nimbus Roman No9 L, Times New Roman, Times, Charter, serif
font.sans-serif     : Helvetica, Bitstream Vera Sans, sans-serif
font.monospace      : Monaco, Ubuntu Mono Regular, Bitstream Vera Sans Mono, Andale Mono, Nimbus Mono L, Fixed, Terminal, monospace

```

Some things that do not solve the problem for me:

1. Delete files in `~/.matplotlib/` (i.e. `matplotlibrc`, `fontList.cache`, `tex.cache/`)
2. Change the `font.family` property in `~/.matplotlib/matplotlibrc`
3. Re-install matplotlib after an `apt-get purge`

The versions I use are:

* matplotlib 1.1.1~rc1+git20120423-0ubuntu1
* Python 2.7.3
* IPython 0.12.1
* Ubuntu 12.04