A bid to block a TV service that allows viewers to automatically skip adverts on recorded shows has been rejected.
Fox had called for a preliminary injunction on Dish Network's Autohop ahead of a copyright ruling.
Broadcasters Fox, Comcast, NBC and CBS have each sued Dish Networks, saying the show recordings are unauthorised.
Fox said it would appeal against the ruling. It says Autohop is "destroying the fundamental underpinnings of the broadcast television ecosystem".
But Dish called the decision not to grant a preliminary injunction a "victory for common sense".
Its Hopper digital video recorder can record and store prime-time content from the four major networks for up to eight days.
And the Autohop feature lets viewers skip advertisements completely - rather than fast-forwarding through them - at the press of a button.
Fox had sought a preliminary injunction on Autohop ahead of a ruling on whether the Hopper service was infringing copyright by enabling unauthorised copies of the shows to be made.
The ruling has not been released publicly in order to give the companies involved time to remove confidential commercial information.
However, according to a statement released by Dish Networks, Judge Dolly Gee ruled that Fox was unlikely to be able to prove that it had suffered irreparable harm from the copies Dish's service made.
Fox said it was "gratified" the judge had ruled that the stored programmes did constitute copyright infringement.
"Dish is marketing and benefiting from an unauthorized [video on demand] service that illegally copies Fox's valuable programming," it added.
Dish, which has 14 million customers, argued that Autohop was simply making it easier for viewers to do something most do already - fast-forward through unwanted adverts.