Today, Microsoft released the December Customer Technology Preview (CTP) of their next operating system, Windows Vista. This new CTP is tagged build 5270.

Greetings Windows Beta Testers! The Windows beta team is pleased to announce the availability of Windows Vista and Longhorn Server build 5270. This release is the December Customer Technology Preview (CTP). This build is not beta quality but is offered as a preview or our progress towards Beta 2. It will allow you to confirm bugs that have been fixed and begin testing features that have been added since build 5231. Please obtain a new product key for build 5270 from the Microsoft Connect website (http://connect.microsoft.com) and download this release as soon as possible. No media will be sent; this release is available as a download only. You will need a new version of the Microsoft Beta Client to report issues. Release notes are available which call attention to some of the issues we are already aware of. Please take a moment to read them then join us in the newsgroups to discuss your experience with Windows Vista. Important notes: Please use the link above to obtain a new product key This build must be clean installed. Upgrades are not supported but will be enabled in later builds. Download images are DVD only. No CD images will be made available for this build. Both Vista and Longhorn Server are available in the same image you only need a separate image if you wish to test Longhorn Server Core. The initial release is English only, German and Japanese are planned to follow within 2 weeks The following are available with this release: Windows Vista (x86 and x64) Windows Longhorn Server (x86 and x64) Windows Longhorn Server Core (x86 and x64) Windows Platform SDK (Available Shortly) Windows Driver Development Kit We look forward to your feedback on this new build!

Related Link: Microsoft Windows Vista Build 5270 (December CTP) Feature List