Some iPhone users across the globe complained of malfunctioning alarms on the first working day of 2011, even after Apple reassured users that its phones' built-in clocks will work from Monday.
Bloggers, Facebook and Twitter users complained they missed flights or were late to arrive at work, as the alarm built into Apple's iPhone failed to go off for a third straight day for some users.
"Come on Apple, I thought the iPhone alarm bug was supposed to 'correct itself' by this morning?" tweeted Julie Morgan, a public relations executive in Portland Oregon, on the social networking site. In an interview, she added, "Luckily, my internal alarm clock went off."
Similar messages were sent by iPhone users in Britain, Netherlands and other European countries.
The problem was not limited to the iPhone, with some owners of other Apple products, such as iPod music players, also complaining of a similar problem with their alarms.
"Apple certainly needs to fix it as soon as possible, but I doubt this will impact sales or reflect negatively on Apple itself," said Gartner analyst Carolina Milanesi.
Apple was not immediately available for a comment in Asia and Europe, but it said on January 2 that it was aware of the problem with non-recurring alarms and that the iPhone's alarm would begin functioning normally again on January 3.
Some users said their alarms worked properly on Jan 3.
"This is not a major issue for Apple, but it is sad that they have the same error on vital dates," said John Strand, founder and chief of Danish telecoms consultant Strand Consult.
The iPhone alarm system failed to recognize changes in daylight saving time in 2010, causing some users to sleep in an hour longer, according to media reports.
The last time Apple was embroiled in publicity problems was in July last year after the launch of the iPhone 4, when reports about bad reception snowballed and forced the company to call a news conference to address the issue, dubbed "antennagate."
This had no visible impact on Apple's sales as the company sold more than 14 million iPhones in July-to-September quarter, more than ever before. It is now the world's second largest smartphone manufacturer behind Nokia.
Apple shares rose $7.06, or $2.19 percent, to $329.63 in afternoon trading on the Nasdaq after Oppenheimer raised its target price to $385 from $345 per share on optimistic sales estimates for the iPad and iPhone.