我在“项目”和“目标”中设置了“iOS部署目标”，从7.1到8.0，重新启动Xcode(点击“退出”)，它工作了。

升级XCode以确保它支持当前设备上的iOS版本。

(就我而言，我的手机使用的是iOS 9.1.x)但XCode版本是7，支持iOS 9.0设备)

For most people the cause of the problem is probably mismatch between Xcode, device version and app target version. If versions are not a problem for you, most likely is that the device (iPhone/iPad) has been used with another Mac to copy apps to. This happens particularly more with a team environment where an iDevice can be used between team members. Xcode knows some other developer's Mac has connected to this device, it will show up as "Ineligible". But the previous Mac that connected to it, it will show up as normal. The quickest work around is as shown by joshstaiger among others: Go to Xcode ->Product->Destination Select the ineligible device as target. It should work.

我也遇到过类似的问题，对我来说，我已经升级到iOS8，并更改了Xcode项目的名称。对我来说，修复是通过选择管理方案>(+)按钮来创建一个新方案。

执行此操作后，我的设备列表返回。

对我来说有用的是安装XCode 6.1(兼容iOS 8.1)

我只是重启了我的Mac和iPhone 6，问题就解决了。我从不需要改变我的部署目标。