im also having this problem on my iphone SE. steps i have tried:
- restarting computer and phone
- updating itunes and the phone
- trying to backup on another computer
- clearing out storage space on itunes drive
- deleting any old apps (though none said anything about not supporting iOS 11)
- clearing space on the phone itself
- deleting and reinstalling itunes
- backing up to icloud (not enough space)
every time i get the same message...i have no issue syncing my phone (it just skips the backing up part giving me the error message) and i have no issues backing up my ipad or my moms phone on this computer (using the same cable and the same usb port)...so i really dont know what to do at this point...and sorry but apple support has not been very helpful when ive called....i have not tried restoring the phone as the only backup i have available is from over a year ago (i was away from this computer for quite some time) which is why i also havent tried restoring to factory settings
nothing seems to be working....pls help