Greyed out songs when trying to add from iTunes to iPhone? I just got an iPhone 4 and downloaded the most recent version of iTunes onto my computer because I had a version that was too old. It told me I needed to convert the songs to create an AAC version of my library in order to sync them to my iPhone, which I had not synced because I didn't want to lose the existing music. When I converted the files, they copied to the phone, but are greyed out and won't let me play them, could somebody please help?
Try playing the greyed out songs directly on your iPhone. If you cannot do that, do the following. 


Ensure that the greyed out songs are indeed playable within your iTunes library (not within the iPhone section of your iTunes library)
Connect your iPhone to your iTunes, navigate to your iPhone section > music, select all greyed out songs and delete them. 
Make sure that the "Sync music" and "Entire music library" options are ticked under the "Music" tab and sync your iphone once again with iTunes.


This should resolve the issue.