McDonald was last seen leaving her Midland County, Texas home at 1:00 a.m. on April 2, 2009. She was driving her silver Lincoln Towncar with a large silver tiger sticker on the back window and Texas license plates numbered LCN-864. McDonald liked to go for drives at night, leaving her two young children asleep in the care of her husband. She has never been heard from again. Nearly two weeks after McDonald's disappearance, her car was found at a roadside park along Interstate 20, at Mile Marker 70 in Monahans, Texas. It had been there since a few hours after she was last seen.

Since McDonald's disappearance, she hasn't used her cellular phone. She wasn't taking any medications that could cause her to wander away. She was having financial problems, however, and expected her car to be repossessed. Police consider her disappearance suspicious; it remains unsolved.