Right. I found the file at C:/Users/Erik/.streamlit/config.toml. Typo on my part.
I was able to recreate the error. I am deploying my app to Heroku. I have a setup.sh file. If I run the setup.sh file outside of the Heroku environment (e.g., double click the file on my computer), it populates the config.toml file with the single line. The setup.sh file contents are pasted below, so you can see how this is happening. I’m running Windows 8.1 locally.
mkdir -p ~/.streamlit/

echo "\
[general]\n\
email = \"your-email@domain.com\"\n\
" > ~/.streamlit/credentials.toml

echo "\
[server]\n\
headless = true\n\
enableCORS=false\n\
port = $PORT\n\
" > ~/.streamlit/config.toml