Can't sync my 3GS: 'filename already exists'

[renevda]

Since a few days (from before iOS4) I get a pop up when I sync my iPhone. 'Can't synchronize the iPhone 'iPhone 3GS from René van den Abeelen'. The filename already exists' is how I translate it.
Filename? What filename?

It seems the synchronisation is continuing but nothing more happens so at last I click OK and I can disconnect. On the Mac iCal-data are not synchronised, on the phone a new ringtone is missing and perhaps there are more items that are not synchronised.

I haven't got a clue what the problem is. Can anyone offer advice?
Thanks very much!!!

 

[iphoneuser2040]

i had this same problem when i updated to iOS4, but seemed to sort itself out after I restored my phone. You could try that? Just hope you have a recent backup...

 

[snipper]

I have the same problem, right after I updated to iTunes 9.2. I did this because you need it to update your iPhone to iOS4.

@ renevda Did you restore it and did it work?