VMware has announced an upgrade to its application virtualization software, which aims to reduce the cost of deploying new desktop programs to end users.

The software allows IT departments to package a desktop application into a single executable file, which can then be deployed and run by the end user without altering the host machine's operating system, such as its file system or registry files.

The idea is to avoid the software conflicts that can "break" existing desktop applications, and to reduce the amount of testing IT departments have to do before they deploy a new application.

VMware bought the software earlier this year when it acquired a company called Thinstall. On Tuesday it announced that it has rebranded the product as ThinApp, and said a new version, ThinApp 4, will go on sale within 30 days.

IT departments can package an application with ThinApp and then deploy the package on computers running almost any version of Windows, including XP and Vista, said Jerry Chen [cq], VMware senior director for enterprise desktops. ThinApp can also run two versions of the same program, so a user could run Internet Explorer 6 and 7 on the same desktop if they needed to.

One drawback has been that virtualized applications can't communicate with each other, because they operate in a their own virtual software "bubble." If a user is running virtualized Microsoft Word, for example, and clicks on a Web link in a Word document, the application can't call on Internet Explorer to open the Web page.

In ThinApp 4, a new feature called Application Link allows administrators to create these links between virtualized applications. An administrator could create a separate package for a Java or .Net component and share it across multiple virtualized applications, Chen said.

The other main enhancement is Application Sync, for delivering bug fixes and other updates. "All I have to do is virtualize the new version, post it on a Web server, then the existing version detects that there's been a change and downloads the differences," Chen said.

Michael Rose, a research analyst with IDC, said products like ThinApp have a lot of promise, but he said they may be ahead of the market because most people are still coming to terms with the basics of desktop virtualization.

"VMware has done a good job in getting out ahead of this but I don't think many people are considering it just yet," he said. "Desktop environments are really complex and I don't think there's enough maturity in these platforms yet to see really broad-based adoption. There will be, but it's a matter of time."