Fixing Theano issues after updating to MacOS Monterey

After upgrading to MacOS Monterey I stated getting Theano related errors. This often happens after a MacOS update.

I managed to get this working with these steps:

  1. Install Xcode with xcode-select --install run in the terminal, then follow the install instructions. That alone did not solve the problem.
  2. But my problem was fixed after running export CPATH=/Applications/ which was taken from here.

After that my problems were solved. I made sure to quit and restart Terminal, Iā€™m not sure how important that step was.


  • This was on an M1 MacBook Air running regular (not Apple Silicon) Anaconda Python install.
  • I did not have any issues at all after upgrading to MacOS Monterey on my 2019 iMac (non Apple Silicon).