July 29 (Reuters) - Seagate Technology forecast first-quarter revenue slightly below Wall Street expectations on Tuesday, hurt by weak demand for its storage devices amid ongoing uncertainty in the personal computer market, sending its shares down 5.6% in extended trading.

Despite optimism surrounding on-device AI features and an anticipated Windows 11 refresh cycle, end-market demand for PCs remains uncertain as consumers navigate a shifting macroeconomic and global trade landscape.

The company expects revenue for the first quarter ending September to be $2.50 billion, plus or minus $150 million, falling short of analysts' average estimate of $2.51 billion, according to data compiled by LSEG.

Adjusted profit for the quarter is projected at $2.30 per share, plus or minus 20 cents, compared with the consensus estimate of $2.33 per share.

Growth in the PC market remains uncertain after customers advanced shipments into the first half of the year amid trade negotiations, according to analysts. Global PC shipments rose 6.5% in the June quarter, according to data from International Data Corporation.

For the fourth quarter ended June 27, Seagate reported revenue of $2.44 billion, slightly above analysts' estimate of $2.43 billion.

The company posted adjusted earnings of $2.59 per share, topping expectations of $2.45.

Seagate said its first-quarter forecast accounts for the net dilutive impact of its exchangeable senior notes due in 2028 and anticipates minimal effect from current global tariff policies.