I'll submit a pull request to address this - but am just trying to get more information about whether I've missed something first. I've written the following demo: https://github.com/juliangamble/logback-file-lock-bug It shows a logback configuration with parent and child file references to the same file - and the parent append requests succeed and the child requests fail. My question is: Is it a bug that logback doesn't warn that you've referred to the same file twice and just silently fails? (If so - we can fix this!) Cheers Julian