The stock was falling 6.88% to $47 a share, after having gained 0.88% in regular hours.
Earnings per share came in at an adjusted 17 cents, missing Wall Street estimates of an adjusted 46 cents. Revenue was $3.67 billion, missing analyst's estimates of $3.68 billion. Last year's third-quarter EPS showed Western at $3.63 on $5 billion in revenue.
"Market conditions have generally been consistent with our expectations, and while the business environment remains soft, there are initial indications of improving trends," said Steve Milligan, CEO of Western Digital. "Our expectation for the demand environment to further improve for both flash and hard drive products for the balance of calendar 2019 is largely unchanged.
Western Digital issues guidance on its earnings call.
The stock is up more than 30% year-to-date.