iOS 8 cannot be installed - what to do?

There are several reasons why iOS 8 cannot be installed. We'll show you how to solve the problem.

Server problems: iOS 8 cannot be installed

iOS 8 was released for users in Germany on September 17, 2014 at around 7 p.m. Millions of iOS devices are trying to download the new Apple operating system at this time and in the hours and days after.
Since the upgrade is around 1 GB, Apple's servers are heavily loaded.
If there is no specific problem with your iOS device, unfortunately only one thing helps: wait. The servers are simply overloaded.

Large updates are always fraught with problems at Apple. Sometimes all data is deleted after the upgrade, sometimes nothing happens.
In our test with an iPhone 4S we also had to download iOS 8 twice. After the first alleged installation of iOS 8, we simply returned to iOS 7 after two hours.

To download and install iOS 8, the iOS devices require up to 6 GB of free space, depending on the type.
In the settings you will find the currently free storage space under the "General" category and the "Use" item. You can delete memory-eating apps directly here.
The easiest way, however, is to delete individual music albums or the entire collection from the iOS device. After the update, this can easily be uploaded again.

If the download of iOS 8 via WLAN does not work, simply connect your iPhone, iPad or iPod touch to your computer using a USB cable.
iTunes will ask you directly if you want to download and install iOS 8. In some cases, the process via iTunes works much better than on the device itself.

If problems or error messages occur during the installation of iOS 8 that have nothing to do with server problems, it is advisable to reset the device.
Connect your iPhone, iPad or iPod touch to your computer with a USB cable and start iTunes. You can then select the device in the top right corner and click the "Restore iPhone" button. All data and settings are deleted and iOS 8 is then installed.
Note: Save a backup of all important data such as photos on your computer beforehand. Synchronization via iCloud stores most of the relevant data for you.

We will show you how to request the desktop version in Safari under iOS 8 in the next practical tip.