A consumer advocacy group is blasting RealNetworks for installing adware and other software without properly notifying its users.

In a report published Thursday, StopBadware.org faults the latest version of RealPlayer for secretly installing its Rhapsody Player Engine during the RealPlayer installation.

"RealPlayer 11 does not disclose that it installs Rhapsody Player Engine, and does not remove the software when RealPlayer is uninstalled," Stopbadware says in the report.

Rhapsody Player Engine is required to access RealNetwork's online music service. But because users are not told that they have installed the product it could become a liability, using up the computer's hard-drive space or processing power, or even creating a security risk for consumers if bugs are discovered in Rhapsody, said Maxim Weinstein, StopBadware's manager.

Both RealPlayer 11 and the older RealPlayer 10.5 software are both considered "badware," the report states.

Real Player 10.5 suffers from a different issue, however. Users who download the software without filling out the RealNetworks product registration page end up with a piece of software called Message Center, which then proceeds to deliver ads to the user's computer. "It's installing, essentially, a piece of adware without giving users information about that up front," Weinstein said.

RealNetworks spokesman Ryan Luckin said a check-box on the registration page is used to notify users that Message Center would be installed. Users who clicked through the registration page without filling out any information would have the software installed.

Although the issue was fixed in version 11 of the player, RealPlayer 10.5 is automatically downloaded via the Firefox browser's "Missing Plug-in" feature and is still widely used, Weinstein said.

Until RealNetworks is up-front with users about what software they're actually downloading, StopBadware recommends that consumers avoid its media player.

Luckin called the Rhapsody issue an oversight. "The fact that when you uninstall RealPlayer we don't go back and uninstall Rhapsody is an oversight and is something we should address in the future," he said.

A widely used alternative to Apple's QuickTime and Microsoft's Windows Media Player, RealPlayer has a history of making invasive changes to users' computers. The Message Center software has come under fire in the past, and in 1999 computer security consultant Richard Smith discovered that the software was quietly sending information to RealNetworks servers.

StopBadware's findings apply only to the Windows versions of RealPlayer's software, Weinstein said. RealPlayer also runs on other operating systems, including Mac OS X and Linux.

Supported with funding from Google, Lenovo and Sun Microsystems, StopBadware evaluates software and warns consumers of products that engage in deceptive behavior, such as tracking user behavior or installing programs without telling consumers.

Although RealPlayer 10.5's Message Center feature may be more noticeable and annoying, Weinstein said Real Networks should fix both problems as soon as possible. "It's hard to say that one is worse," he said. "They're really two sides of the same concept of just not telling users what's going on."