Directions for syncing iPhone lead to a dead end A friend gave me an iPhone 4, which I'm trying to use. I was directed to this website: https://support.apple.com/en-us/HT201252, which tells me to sync the phone using iTunes. But (a) the File > Devices menus that this site directs me to use lead to a dead end in the form of a totally greyed-out menu; and (b) I keep getting an error message saying that the device timed out. I'm running Yosemite on a MacBook Pro.   Any help gratefully received.
Try restarting the iPhone (home button + power button 10 seconds). Plug in the 
iPhone and see if iTunes recognizes it.

If that doesn't work, you should try connecting it in Recovery Mode:

https://support.apple.com/en-us/HT201263