Could not find the matplotlib data files

I've fixed the problem by downgrading matplotlib to version 3.0.3 Using this command: python -m pip install matplotlib==3.0.3

hi i faced the same problem too when generating script using pyinstaller (im using python 3.7). The problem is solved when i installed:

pip install matplotlib==3.0.3

The only thing that worked "sustainably" for me is to also downgrade to and earlier version of Matplotlib version 3.1.3. I can now use pyinstaller. I can also run all program without that horrible warnings and stuff that it gives.

I used pip install matplotlib==3.1.3. make sure you uninstall all previous matplotlib.