Mkmk error after exporting font

Hi, I was wondering what this error is and how to fix it. Keeps showing up after export, when reopening file, not before though. Thanks!

Opening a .otf file means decompiling the binary info inside the font. That is not easy and can fail. So an error in the decompiled feature code doesn’t mean that the .otf file is wrong.

@ivg If you want to see how the OpenType features and lookups looks inside the font file, you can install the fontFeatures Python library by Simon Cozens, and then run the otf2fea utility.

# in macOS Terminal
# install the library
pip3 install fontFeatures
# ran the utility
otf2fea YourFont.otf

Perfect! Thank you both.