How to Start Apple Mobile Device Service

Windows
1. Close iTunes. Disconnect your iPod or other related device from your computer by unplugging the device's cable from the USB port on your computer.
2. Click “Start,” type 'services' in the Search field and press 'Enter.'
3. Select “Apple Mobile Device” in the Service (Local)' window.
4. Click the “Stop” link on the left. Alternatively, you can right-click 'Apple Mobile Device' and select 'Stop' from the context menu.
5. Wait for about 10 seconds and select 'Start.' Alternative, right-click 'Apple Mobile Device' and select 'Start' from the context menu.
6. Open iTunes and reconnect your iPod/related device.
Mac
7. Close iTunes. Disconnect your iPod or related device from your computer by unplugging the device's cable from the USB port on your computer.
8. Click on your Mac's Hard Drive icon and select the “Applications” folder.
9. Locate and drag the “iTunes” folder to the “Trash” on your Mac's desktop.
10. Click “Go” and choose “Go to Folder” from the Finder menu. Enter “/System/Library/Extensions” in the dialog box. Click “Go.” Locate and drag the “AppleMobileDevice.kext” file to the “Trash.”
11. Click “Go” and select “Go to Folder” from the Finder menu. Enter “/Library/Receipts/” in the dialog box. Click “Go.” Locate and drag the “AppleMobileDeviceSupport.pkg” file to the “Trash.” You may be prompted for an administrator password. Enter your system's password to complete the deletion process.
12. Restart your Mac. Select “Finder” and choose “Empty Trash” once your Mac has restarted. Restart your computer again.
13. Reinstall the latest version of iTunes on your Mac (see Resources). Once you have installed the program, open iTunes and reconnect your iPod or related device.