Hi, Sorry to jump in without background, but on Win8 I think it would make more sense to use the built-in hardware ID that WinRT provides, as below, rather than using createUUID to demand-create a device ID. (The hardware ID would obviously survive a localStorage reset.) private string GetHardwareId() { var token = HardwareIdentification.GetPackageSpecificToken(null); var hardwareId = token.Id; var dataReader = Windows.Storage.Streams.DataReader.FromBuffer(hardwareId);
byte[] bytes = new byte[hardwareId.Length]; dataReader.ReadBytes(bytes); return BitConverter.ToString(bytes); } I've created a Jira item to this effect. https://issues.apache.org/jira/browse/CB-1702 Hopefully I'm not missing something! As I suggest, I'm new to any prior discussion. Thanks, Matt --------------------------------------------------------------------------------------------------------------------------------------- Matt Baxter-Reynolds (@mbrit) Independent software development consultant, speaker, author, and trainer. Windows 8 Specialist. Read my blog at ZDNet. Talk to me on Twitter. . Coming December 2012: "Programming Windows Store Apps with C#" (O'Reilly) Come along to the London Windows Store Apps Developer Group On 24 Oct 2012, at 05:30, Mingfeng Wang <mingfengwan...@gmail.com> wrote: > Hey, > > Now the Device UUID is saved in localStorage of html5 for Windows8, so > it is the same if all the projects are in the same domain. > I want to use a file instead of localStorage, is it necessary? And > where can I save this file? > > Mingfeng