I have written some LaTeX commands in a separate file, say
foo.tex and include them in my LaTeX document.
Only after I edit
foo.tex with Notepad (default editor in Windows), I get the following error message when compiling :
Unicode char \u8: not set up for use with LaTeX
I suspect that Notepad alters my text file, which is saved as previously with the UTF-8 encoding. How can I prevent it ?