I dont know how or why this started, but I am not able to sync my iphone 4 to itunes. Music library has new songs that I just added, however they will not sync to iphone. When I perform the sync, I am selecting FILE > DEVICES > SYNC " ". When I do this, the iphone acts as if it has sync'ed, when in fact it has not. I do not get any kind of error message.
To diagnose the issue, I downloaded latest version of itunes, latest OS, checked a few of the basic settings in itunes, and still no sync. I dont sync and add music very frequently, so this issue may have started 6 or 9 months ago, and never noticed.