iphone 4 wont sync to itunes

ive notice alot of people have looked at this im not the only person having the same problem, itunes recognises my iphone i click for it to sync and at the first stage it fails telling me that sync session failed to start this takes a while to come up can someone please shed some light on this please

I am having the exact same problem - the error messages says that the phone could not be synced because the sync session failed to start. I have tried this two days in a row and it still won't sync. I have tried connecting, reconnecting, hard turn off, turn on. Nothing seems to work.

When I try to open iTunes on my iPhone 4, I get a black border across the top of the screen with "History" in white text. The rest of the screen is white except for three parallel gray bars in the middle of the screen. Underneath the bars, it says "You don't currently have any preview history". How do I fix this?

I can't sync from iTunes V12.1 to iPhone 3gs. I've been trying for 2 hours or more. Why isn't there a sync button?