For those Windows users who suddenly cannot see their device in iTunes. Here's a solution that has worked.
I know this seems to be an emerging issue ever since the update to iTunes 11.1.4, some iPhones or other iOS devices are not showing up in iTunes or syncing. I'm not sure if Apple really knowns of this issue, but tech support has a (mostly) sure fire way of resolcing this issue. It's only for Windows computers though.
Go to the article http://support.apple.com/kb/ts1538 and follow the Section 5 Verify Apple Mobile Device USB driver is installed. When you clik on that section, go to your version of Windows (it seems to be happening mostly across Windows 8) . And then to the section: If Apple iPod, Aple iPhone, or Apple iPad is listed.
The gist of what you need to do:
Windows 8 (since it seems to be the most affected) move your cursor to the upper ight corner of your screen) and click on the Magnifying glass. Type in devmgmt.msc and this should bring up the Device Manager. Onc eyou are in the device manager, look for the "Portable device" or "Universial Serial bus Controller" list, and you should see the "Apple iPhone/iPad/iPod" listed. Onc eyou see it, right click it, choose "Update software driver." Now, IT WILL SAY THE DRIVER IS UPDATED. I CANNOT STRESS THIS ENOUGH. Select "Browse my computer for driver software." Onc eyou choose that, select "Let me pick from a lsit of drivers on my computer." You should see the option "Have Disk." Choose that. Again, I KNOW you do not have a physical disk, but the file we need is already on your computer. After Hard Disk, choose Browse again. Follow this file path to the file we need: C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers.. In the Driver's folder, you should see the "usbaaple" or "usbappl64" (if you have the 64 bit for Windows). Double click on that file, and hit OK. The file should install, and once it's finished check your iTunes!!! You may want to unplug your device and plug it back it before doing all of this. I REALLY hope this works for you all as well!
iPhone 5s, iOS 7.0.4, Resolution for emerging issue