Bug summary Once I type " import matplotlib.pyplot as plt" and run it, jupyter always returns： ＂Matplotlib is building the font cache; this may take a moment.＂ ＃Then the return messages will end up as ...

How did you install Matplotlib (which conda channels and did you mix pip and conda?) Is that the full traceback? It in hard to say much definitive based on this, but my guess is that you are seeing ...