Hi, I have submitted a patch (http://www.python.org/sf/1704547) that allows os.rename to replace the destination file if it exists, on windows. As part of discussion in the tracker, Martin suggested that python-dev should discuss the change. Currently, os.rename() on windows uses the API MoveFile() which fails if the destination file exists. The patch replaces this API with MoveFileEx() and uses the flag MOVEFILE_REPLACE_EXISTING which causes the destination file to be replaced if it exists. However, this change is subtle and if there is any existing code that depends on current os.rename behaviour on windows, their code is silently broken with (any) destination file being overwritten. But the functionality of replacing is important and I would like to know the best of way of supporting it. If it is deemed that this change is not good to go in as-is, how about having an optional parameter to os.rename (say, win_replace) that can be used by callers to explicitly request replacing? I must also point out that the patch uses another flag MOVEFILE_COPY_ALLOWED effectively allowing renamed files to be on separate file systems. The renaming in this case is not atomic and I used this flag only to support current functionality. It is not a bad idea to disallow such renames which brings it in line with the behaviour on many unix flavors. This also has the potential to break code but not silently. Lastly, I found an old discussion about the same topic by this list. http://mail.python.org/pipermail/python-dev/2001-May/014957.html Even though Guido indicated that he doesn't support API change in this thread, I am posting again as I did not see any one mention MoveFileEx() in that thread. Thanks, Raghu.