A “Software Update Unavailable” problem was commonly reported for users trying to download Apple’s iOS 7, most likely because a huge number of people are trying to download the upgrade at the same time.
Likely millions of people were attempting to download the software after it was released midday on Sept. 20. Many got the “Software Update Unavailable” error message, which reads “Software Update is not available at this time. Try again later.”
Users said the error occurred toward the end of the updating process.
Others got messages including “Software Update Failed” and iTunes users got “Error 9006.” Some reported issues with iMessage after they downloaded iOS 7.
More about those errors and how to solve them can be found here.
As some people pointed out, however, it simply takes patience and persistence to download the new update.
Twitter was ablaze with messages about the iOS 7 error messages.