Its reputation has already been tarnished by iPhone 4 antenna problems, but now Apple faces a new PR nightmare as iPhone 3G owners say their handsets are barely usable after Apple pushed out a software update.
The iOS 4.0 update was recently delivered to iPhone 3G users when they connected the device to their computer.
Many users, including members of New Zealand online technology forum Geekzone, have said their phones now regularly lock up and take an eternity to perform basic tasks like web browsing.
"My friend running a 3G installed the update and it is incredibly slow," said one member. "We were trying to change his lock screen image ... and it honestly took more than 4 minutes ... something i can do on 3GS [iPhone] in about 25 seconds."
Independent technology consultant Colin Jackson advised iPhone 3G owners not to update to the software, but said those with an iPhone 3GS should be fine.
"It doesn't seem to be fast enough to handle the operating system, frankly."
He had updated his iPhone 3G and found the text messaging application often took a minute to load – meaning he had had problems using text-to-park machines.
Apple had released an iOs 4.0.1 update but he understood that was only an attempt to fix the iPhone 4's antenna problems.
The issues come after Apple was heavily criticised for failing to properly test the new iPhone 4, which will be launched in Australia and New Zealand on July 30. Vodafone will be selling the phone.
Widespread antenna and reception issues were reported, and Apple chief executive, Steve Jobs, was forced to get on stage to respond late last week. He offered all iPhone 4 buyers free "bumper" cases that reportedly fix the antenna problems by limiting hand contact.
Users in Australia have been complaining about the update on internet forums.
"I'm so pissed off with Apple, my phone was perfect before the update and now I want to smash it," wrote one user.
Apple said it recommended iPhone 3G owners update to iOS 4.0.1. It said anyone with issues could contact Apple or their local Apple retailer.