Hi all, Just spent some hours banging my head on a brick wall with this one. I've got a program where I have to open a file given its pathname as a String. I've got code that works fine on Mac and Linux, but it'll only work on Windows XP if the pathname for certain file types - for example .m4a will open with iTunes quite happily, but .avi produces this error: Code: java.io.IOException: Failed to open file:/C:/Documents%20and%20Settings/Chris/Desktop/In.Treatment.S01E21.avi. Error message: The parameter is incorrect. at sun.awt.windows.WDesktopPeer.ShellExecute(Unknown Source) at sun.awt.windows.WDesktopPeer.open(Unknown Source) at java.awt.Desktop.open(Unknown Source) (the stack trace goes on a while, but I won't type it all out unless more is needed) I've tried this with the default application for .avi being Windows Media Player and VLC (that error is with the latter set, the former gives a similar but slightly different error). Does Windows XP just not fully support the java.awt.Desktop class? Any ideas very welcome!