Problems ranging from errors contacting update servers to device storage space constraints have been plagueing those trying to download Apple's latest mobile operating system, iOS 8.
iPhone and iPad users have taken to to social media to vent their frustrations. The requirement of 5.8GB of space on the device for the download to take place has meant that many users have been advised to delete or transfer pictures, films, music and other files in order to accomodate iOS 8.
Twitter users vexed by the issue caused enough furore that at one point the topic trended ahead of the Scottish referendum on the social network.
iOS 8 is available for all versions of the Apple iPhone dating back to the iPhone 4S, and all iPad's from the iPad 2 onwards.
Key features of the new operating system are third-party keyboards, iCloud Drive storage, and the search system Spotlight.
Other issues have plagued iOS 8 on the day of its public release, including a bug with the widely-anticipated HealthKit platform.
Yesterday Apple announced that the health and fitness application was experiencing problems that meant its launch would be delayed.
"We discovered a bug that prevents us from making HealthKit apps available on iOS today. We're working quickly to have the bug fixed in a software update and have HealthKit apps available by the end of the month," Apple said in a statement.
Early reports have suggested that the demand for iOS 8 has been higher than any previous iOS system.
Virgin Media said that iOS 8 caused a 10% increase in peak download traffic, making it the busiest ever day on its network.
"From what we've seen so far, the release of iOS 8 has driven more internet traffic than previous updates, with increased demand likely to last until the weekend," said Martin Groundsell, head of broadband access at Virgin Media.
"Even though the iOS 8 release has generated the biggest download day so far, our fastest customers have been downloading iOS 8 in as little as 61 seconds at peak times with no major problems reported."