Microsoft has quietly released a beta version of an Active Directory client for Windows NT 4.0 machines.

The move is a reversal of the company's stance following the release of Windows 2000 earlier this year which was that there "won't be an Active Directory client add-on for any operating systems other than the Windows 9x platform".

It has also been viewed as an attempt to woo users into adopting its directory technology, which is a central feature of Windows 2000.

The release of the software will allow users to run NT 4.0 clients in an Active Directory domain. The issue is important because directories provide a logical and accessible way of storing complex user and system information. This means information is stored only once, which enables the straightforward rollout of services such as single sign-on and the management of back-office applications.

The Active Directory client for NT 4.0 will be released with the forthcoming Service Pack 7 for NT 4.0 in the first quarter of next year.

Neil Laver, Windows 2000 product marketing manager at Microsoft, said that with the release of the software Microsoft is trying to lower the barriers to Active Directory deployment, which he said provided better management of Windows 2000 environments.

"The client software will allow implementation of Active Directory for some of our customers, whose server infrastructure rollout is running ahead of client deployment," said Laver, who admitted that an Active Directory client for NT 4.0 had been slow to develop.

The client will allow Active Directory features such as the ability to log on to a domain controller, password changing and access to software interfaces within Active Directory. However, it does not provide support for its security protocol Kerberos nor access to Intellimirror management technologies, for which an upgrade to windows 2000 professional is needed.

Dan Kusnetzky, programme director at analyst IDC, said he believes Microsoft is releasing the software after pressure from customers, who wanted a more straightforward way to adopt Active Directory without upgrading client machines.

"Active Directory rollout has proved to be a challenge. In large part this is because Active Directory creates an island unto itself and most organisations don't want to do that," said Kusnetzky.

"Users have held up upgrading because an environment has been created where there are incompatibilities that make it difficult to upgrade," he added.

Kusnetzky said Microsoft has long used the "creative use of incompatibilities" as a way to encourage user upgrades, but that this went against encouraging use of Active Directory, which the software giant is keen to encourage.

In May, analyst Giga Information Group predicted that Active Directory adoption would initially be slow as customers realise how much they need to prepare. As well as forking out up to $1500 per desktop to upgrade to the operating system, customers must reduce their domains and clean up their existing directories to ensure implementation is relatively painless.