Pauline McKee, a 90-year-old grandmother from Illinois, who thought she had won $41.8 million on a video penny slot machine, has been denied the bonus after losing a court case.

Pauline McKee was playing the Miss Kitty game at a casino when she won 185 credits, or $1.85.

But a message appeared on screen saying she had also won a bonus worth $41,797,550.16.

The casino refused to pay out, saying the award was a computer glitch.

Pauline McKee, who has 13 grandchildren, sued the casino but the Iowa Supreme Court eventually threw out her case.

“I had my doubts from the start, because that’s a lot of money for a penny machine,” Pauline McKee told the Chicago Tribune.

“I was hoping to help my children out financially, but it wasn’t meant to be.”

The casino argued that the on-screen rules clearly indicated that “malfunction voids all pays and plays”.

At the time of the dispute, the Iowa Racing and Gaming Commission (IRGC) secured the machine and carried out an investigation, sending the hardware and software to an independent testing laboratory.

The investigators found that the software was programmed to allow a bonus of up to $10,000, but they couldn’t work how the multi-million bonus message had occurred.

The machine’s maker, Aristocrat Technologies, said it had been aware of this type of error in the display and suggested “component degradation over time may increase the susceptibility to this rare occurrence”.

The company had alerted casinos to the glitch in 2010 and recommended that they disable the bonus facility as a precautionary measure. The casino evidently had not done this.

The IRGC concluded that the bonus display was “not valid” and that “the slot machine game malfunctioned.”

Pauline McKee sued the casino in 2012 claiming breach of contract and consumer fraud.

The court unanimously sided with the casino in 2013, but the case dragged on when Pauline McKee’s lawyers argued that the IRGC had no jurisdiction in disputes between casinos and their patrons.

They also questioned whether the machine had really “malfunctioned”, as the IRGC had concluded, and whether she had really entered into a contract when playing the game.

The game rules limited payouts to $8,000.

The doughty Pauline McKee saw her case finally rejected by the Iowa Supreme Court on April 24.