“file pdftex.def” not found on Mac OS

After installing MacTex, I still encountered “File pdftex.def not found” error when compiling a tex file in TexMaker/TexShop. Here is the way to solve it:

1. Download from pdfetx-def package from https://www.ctan.org/pkg/pdftex-def
2. Unzip
3. Copy the unzipped folder to the texlive installation directory. Below is what I used: 

   sudo cp -R graphics-def /usr/local/texlive/2016/texmf-dist/