Since 2 Oct 16 after I updated the IOS 10 on my iphone 6, I could no longer do any backups of my iphone data because itunes showed that an invalid response was received from my device.
I thought there was something wrong with my iphone and tried doing the backup almost every week but every time, I received the same error message. I searched the internet for troubleshooting possible problems and for solutions but to no avail. Nothing worked and it was kind of frustrating because I am ready to sign up a new iphone 7 plus contract come end of next month. Unless I can backup my data, my plan isn't going to materialize.
So I visited the Apple Support Service Centre on 16 Nov 16 and waited more than 1.5 hours before getting less than a minute's response from the servicing officer. The good news was his laptop itunes could detect my phone and his recommendation was simply to delete my old itunes app from my laptop and install the latest version of it. I wasn't too happy and was skeptical because I felt like a fool waiting for so long just to get simple reply. I wasn't confident that the solution was as simple as this but in a way, I thought it did seem logical and plausible and I was dying to try it out. But if it doesn't work, I don't know what to do next.
So on the evening of 17 Nov 16, I first made 2 copies of the iphone backup files from my laptop onto my laptop and removable hard disk. That took hours because of the large amount of data. In the end, I decided not to take the risk of deleting my itunes app on my laptop because if I did so and the suggested solution did not work, I really would lose my last backup data from 2 Oct 16.
I found the latest itunes app online and downloaded it instead. It removed my previous backup files and I got a bit worried. When the new itunes managed to detect my iphone, I was momentarily happy but when it didn't manage to sync with my iphone on a couple tries, I was really anxious then. I reloaded the itunes app and tried it again. This time, the backup function started but it took so long that I got more anxious with every minute that passed. I was concerned that even right up to the last bar, the synching might stop abruptly. The backup took hours right into the night.
Fortunately, this time it really worked. So now I managed to backup my iphone once again! The solution is really as simple as deleting an old version of itunes and installing an updated one. I just do not know why this solution wasn't clearly shown online when I googled for a solution to my problem.