On the first use of Spyder, you might get a message in the console pane (bottom right) saying something like:

Matplotlib is building the font cache, this may take a minute

Give it 5 mins then click the x where it says Console 1/A.

All being well, the console will reload without the error. If this worked, you do not need to read this page.

However, some of you might find that this is not the case, and the error does not disappear. If this is the case for you, there is a simple fix:

Close Spyder, then in the start menu open the program called Git → Git Bash.

A black command box should open.

Now, type the following command into the command box, replacing mxxxxxxx with your username, then press Enter:

rm -rf C:\\Users\\mxxxxxxx\\.matplotlib

This deletes a directory (folder) of data that should not be there - it is preventing the Python Interpreter from loading properly.

Now re-open Spyder, give Matplotlib 5 mins to actually build the font cache, then click the x where it says Console 2/A.

All being well, the console will now reload without the error! You should not need to do this again after the first usage.