I just had to debug some really old code that used to work. I found the issue, and it appears that the code broke in going from CF5 to CFMX (yep, it is code that is not used very often). I was using to process file uploads, and was using the destination attribute to specify the full path of the file to be saved. As I said, this used to work. But not anymore because destination expects the path to a folder to store the file in, and no longer accepts a path to an actual destination file. The history in LiveDocs says that in CFMX destination was changed so that a trailing slash was no longer needed in paths, but makes no mention of not being able to use actual destination file names anymore. CF5 documentation clearly says that DESTINATION can be a fully qualified file path or directory, so it appears that we broke something in the port from CF5 to CFMX. Bummer.