I got the above error message in Android ADT Console while trying to debug an Android Project, though the App got installed on the device properly and worked fine normally, but IOException: Unable to open sync connection! message while trying to debug.
If the above steps doesn't solve your problem, check the "USB Debugging" Developer option on your device by going to Settings ( Settings -> Applications -> Development -> USB debugging). Just Uncheck the option and re-check it. You may also try changing the USB port, or trying to work with some other USB cord.
Code2care'smission is to share varied knowledge in technical and non-technical areas gathered during day-to-day learnings and development activities so that our visitors can leverage this portal to find solutions to their queries without re-inventing the wheel. Technical posts include Learnings, Tutorials, Video Tutorials, Code Snippets, Tips-n-tricks.