Monday's release is the version of Vista, thedue by the end of 2006. The preview releases allow Microsoft to more quickly than it could using only a traditional beta program, the company said.
"We're getting more frequent and better feedback than we have ever gotten before in any previous release of Windows, and it is making the product much better," Shanen Boettcher, senior director in Microsoft's Windows Client group, said during a conference call with media on Monday.
The latest test version is being made available to about half a million people, including a pool of technical testers as well as members of Microsoft's MSDN and TechNet developer programs.
Testers will see a number of new features in the update, several of which are on the security front:
Windows Defender, an, is designed to protect Windows PCs against spyware, rootkits and other threats. Windows Defender has improved detection and removal capabilities as well as a new user interface which, according to Microsoft, is simpler and fits better with Windows Vista.
BitLocker Drive Encryption is meant to protect data on computers when lost or stolen. The full disk encryption feature is designed to, or TPM, which offers protected storage of encryption keys, passwords and digital certificates.
Tighter control over removable storage devices lets system administrators centrally block the installation of, for example, USB flash drives and external hard drives. This feature is designed to help prevent corporate intellectual property or sensitive data from being compromised or stolen.
Parental controls designed to let parents limit and monitor computer usage, including setting time limits, restricting Web sites that can be visited and generating reports on computer usage.
Other security related updates include an enhanced firewall and added security in Internet Explorer to protect against.
Other than security, the new Vista preview release promises. For example, USB flash memory drives can be used as additional memory for Windows SuperFetch, a new feature in Vista that caches often-used information, making it accessible faster, according to Microsoft.
Microsoft has also updated the Vista user interface, adding transparent windows, smoother transitions and a redesigned start menu, the company said.
The new preview release also includes an update to Windows Media Player and gives a peek at the successor to Windows XP Media Center Edition with the new Windows Media Center. Microsoft will share more details of Vista's media features at January's Consumer Electronics Show in Las Vegas, the company said.
The latest Vista preview doesn't include all of the features that Microsoft has planned for the Windows XP successor, Boettcher said.
"We're on a path to be code complete by the end of 2005, so we will see that likely in the next release of the CTP," Boettcher said. Microsoft anticipates that the next preview release will be early next year, he said.
Boettcher would not detail which features Microsoft has yet to add to Vista.
Along with the updated preview of Windows Vista, Microsoft on Monday sent out an updated version of itsto testers. The updated Windows Server Longhorn code is available only to participants in a private beta test program and not available via MSDN or TechNet, Microsoft said. To date, the first and only public build of the server operating system was .