Microsoft has launched the latest legal salvo against 21 resellers in 14 US states, alleging they were engaged in the retail of pirate software.

Microsoft said that many of the pirates had been caught thanks the its Genuine Advantage, with all lawsuits concerning copies of the firm's popular Office and Windows XP programs.

According to PC World, which broke the story, many of the resellers have been in trouble with Microsoft before; many of them previously settling out-of-court, although that looks unlikely this time.