Flash saves in Windows, not in Linux, FileReference.save() The code below compiles fine on the Flex 4 SDK on Fedora 15. Mouse click opens the dialog box, I click okay, and a file is saved, but the file is empty. I run the same SWF file (that was compiled on the Linux machine) on a Windows machine, and the created file contains the expected data. Then I broke the FileReference declaration out of the function into the class level, hoping to avoid a known bug and to keep a reference to the file alive outside the function. However, the same problem persists. Hoping to set up a workaround, I added the debug Flash player to my path and ran the file from Flash without the benefit of the browser, and it works. So now a Flex problem has become a Firefox problem, maybe owing to a shady procedure I used to install the plugin without really understanding what was happening. I am running Firefox 5.0. In essence my workflow is fixed, but perhaps people who performed the above will not be able to use projects with FileReference.save()? Should I be worried about this edge case? WriteTheFile.as Original code by Brian Hodge Test to see if ActionScript Flash can write files package import flash.display.Sprite import flash.events.Event import flash.events.MouseEvent import flash.utils.ByteArray import flash.net.FileReference public class WriteTheFile extends Sprite private var xml String private var fr FileReference public function WriteTheFile() void if (stage) init() else addEventListener(Event.ADDED TO STAGE, init) private function init(e Event null) void removeEventListener(Event.ADDED TO STAGE, init) Calling the save method requires user interaction and Flash Player 10 stage.addEventListener(MouseEvent.MOUSE DOWN, onMouseDown) private function onMouseDown(e MouseEvent) void fr new FileReference() fr.save(" lt xml gt lt test gt data lt test gt lt xml gt ", "filename.txt") EDIT addressed answer in code above, but the same problem exists. EDIT This works on the same system when the standalone player is invoked. Therefore this is a browser (FF 5.0) plugin problem.