Datel has filed an antitrust lawsuit against Microsoft after the Xbox 360 platform holder's most recent dashboard update disabled support for third-party memory units.
The complaint, filed in San Francisco federal court by Datel's representatives Howard Rice, accuses Microsoft of "exclusionary, predatory, or anticompetitive acts".
It also dismisses the company's official explanation for the patch - that third-party memory units can be used to cheat on Xbox Live - as a "pretext" for establishing a monopoly on third-party accessories.
Just over a month ago, Microsoft announced it was banning third-party memory units and that anyone using one should buy an official alternative or they would lose access to their profile and saved games.
Datel founder Mike Connors has said that the third-party peripheral company has sold more than 50,000 such unofficial memory units, and that the only difference between its offerings and Microsoft's is that the official unit "offers only one-quarter the memory while listing for the same retail price".
"Microsoft has taken steps to render inoperable the competing Datel memory card for no visible purpose other than to have that market entirely to themselves," said Howard Rice director Marty Glick in a statement (thanks GameSpot).
The lawfirm's statement concluded: "Datel recognises Microsoft's right to innovate. But the recent 'upgrade' to the Xbox 360 is not innovation. It is predatory conduct undertaken to deliberately harm competition with no benefit whatsoever to consumers."
Microsoft has yet to respond.