User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:188.8.131.52) Gecko/20070219 Firefox/184.108.40.206 Build Identifier: I'm using xulrunner 220.127.116.11. I want to clean my profile directory after shutdown but I cannot because Mozilla holds still a reference to the XUL.mfl file. As already written in bug 374315 there is another problem with the XUL.mfl. The problem is that its not released on Mozilla.getInstance().termEmbedding(); I dont have any control over this files because I don't create it. Reproducible: Always Steps to Reproduce: 1. Open Xulrunner in ATF 2. Open a page 3. Try to shutdown 4. Try to clean the profile directory in a shutdown hook. Its not possible because Mozilla holds a reference to it.