I have combed SO and have seen this question asked before but none of the answers are working in my code. I want to load the file board.kv from the subdirectory Board. Whether I use r'Board\board.kv' or R'Board\board.kv' or "Board\\board.kv" or even: 'Board/board.kv' I get OSError: [Errno 22] Invalid argument: 'Board\x08oard.kv' While I don't think it is relevant, I am using PowerShell and tried going through examples using strings in the powershell python interpreter trying various strings like $myString = r'Board\board' $myString Board\\board but I can not get Board\board. Thanks for any help. I have never had a problem like this before. Continue reading...