Microsoft has issued legal threats to stop developers reviving the original Longhorn just after the team posted the first fruits of the project.

According to a blog posting on the site maintained by developers on the Longhorn Reloaded project Microsoft sent a "cesit and decist" (sic) letter to the project leaders asking them to shut it down shortly after the team posted the first release of the project online.

"It deeply saddens me that although Microsoft have known about this project for many months they only issued us with this notice a few days after we started to distribute" the first release, according to a post earlier this month on joejoe.org.Community. "I am just as sorry as you guys are about this, but we got [sic] to think about the community as a whole first."

Longhorn Reloaded Milestone 1 was released 19 May on the project's website, but the post informing users the project has shut down said, download links and any threads about the project will no longer be active.

Microsoft said that though the company "actively encourages and supports independent developers to take advantage of the features available in our platform to create their own applications and services," the Longhorn Reloaded project had violated Windows end-user licensing.

Windows enthusiasts decided to pick up where Microsoft left off with Longhorn's development in October 2006. Microsoft had originally called the client release that became Windows Vista "Longhorn," but switched development plans and names mid-project, though the company continued to use the Longhorn name for the next Windows Server release. That release has since been renamed officially to Windows Server 2008.

The Longhorn Reloaded began the project with a build called Windows 6.0.4074, which Microsoft released at its Windows Hardware Engineering Conference in 2004. Microsoft never said it actually abandoned the Longhorn client, and many predicted that when the Longhorn Reloaded project began it likely would run afoul of Microsoft's legal department.