"Our executive team decided that there were better ways to invest our time and money, and that we didn't need this distraction," Littleson said. "The action we're taking will let us avoid a potential lawsuit."

Acresso did not immediately return an e-mailed request for comment.

Acresso was founded in 1980 and has annual revenue of about $475 million. It also has 3,500 employees at 16 offices globally.

That dwarfs Acresso, which has 375 employees and annual revenues of $115 million.

Flexera will be the fourth name in five years facing long-time users of InstallShield, which was bought by Macrovision in 2004.