Technology companies are leading a broad decline in U.S. stocks that has pulled the Dow Jones industrial average down 200 points.
Apple sank 3 percent after the company pulled a software update for its iPhones late Wednesday as users complained that they weren't able to make calls.
The Dow was down 208 points, or 1.2 percent, to 17,002 as of 10:50 a.m. Eastern time Thursday. The plunged wiped out the Dow's gain of 154 points the day before.
The Standard & Poor's 500 index fell 25 points, or 1.3 percent, to 1,972.
The Nasdaq composite, which is heavily weighted with technology stocks, fell 78 points, or 1.7 percent, to 4,477.
The U.S. stock market sank in early trading following a mixed batch of economic reports. Apple led tech stocks lower after a software glitch.
The Dow Jones industrial average dropped 116 points, or 0.7 percent, to 17,094 as of 10:09 a.m. Eastern. The Standard & Poor's 500 index fell 15 points, or 0.7 percent, to 1,984 and the Nasdaq composite dropped 43 points, or 0.9 percent, to 4,512.
Apple sank after the tech giant had to pull a software update as users complained they could no longer make phone calls. Others complained that they bent their new iPhones by sitting on them. Apple dropped $2.45, or 2.4 percent, to $99.29.
Trading has looked turbulent this week, an abrupt break from a sleepy summer. Concerns about slowing growth in China and falling U.S. home sales knocked the market back on Monday, giving the S&P 500 its biggest one-day drop in more than a month. Health-care stocks led a rebound Wednesday, as the S&P 500 closed with its biggest one-day gain in more than a month.
Claims for unemployment benefits crept up last week. The Labor Department said 293,000 people applied for benefits, but that was slightly lower than economists' forecasts. The less volatile four-week average fell for the second straight week to 298,500. A separate report said businesses orders for equipment plunged last month, mainly a result of a drop in orders for commercial aircraft.
Investors have been looking at economic reports for any signs that the improving economy could lead the Federal Reserve to start raising interest rates. Next week, further clues will emerge from a several key pieces of data, including the job market report for September.
"The existence of major fundamental risks next week means that there is some caution ahead with many unsure of the direction that markets should be heading," said Joshua Mahony, research analyst at Alpari.
In Europe, Germany's DAX fell 1.1 percent while the CAC-40 in France fell 0.8 percent. The FTSE 100 index of leading British shares also declined 0.8 percent.
DOLLAR: The dollar has been gaining on other major currencies. The Fed is widely perceived to be creeping closer to an interest-rate increase, a contrast to the current policy stance of the European Central Bank and the Bank of Japan. On Thursday, the euro fell 0.3 percent to $1.274. The dollar fell to 108.88 yen.
ASIA'S DAY: Japan outperformed the region with the Nikkei 225 up 1.3 percent. In mainland China, the Shanghai Composite added 0.1 percent, while Hong Kong's Hang Seng dropped 0.6 percent.
OIL, BONDS: Benchmark U.S. crude oil edged up 23 cents to $93.03 a barrel on the New York Mercantile Exchange. U.S. government bond prices rose. The yield on the 10-year Treasury note fell to 2.53 percent from 2.57 percent late Wednesday.