How to find corrupted files on mac update#

I first discovered this 'updating of the iphone 4 problem' on the imac. (to complicate this, this apparent bad file on this macbook likely came from my white intel based iMac.

Is there a program that can scan the external HD to find bad/corrupted files? I have Spring cleaning and Drive Genius, neither of which seem to have the features to do such a scan (they do have disk scan, which I have run, along with Apple's Tech Tool, and all such scan operations have show no problems)

How to find corrupted files on mac update#

I suppose I could go through the tedious process of transferring one program/file at a time onto the macbook, then trying the update again, but I can't do an update after each transfer because there is no new update to download, as they come out only every so often. So I guess somewhere in what I transferred back onto the macbook is a bad file. However, after I drag and dropped many, but not all, of my programs and files from the saved data on external HD back onto the macbook, and tried an update on a different iphone 4 (in our family plan), same problem. In this scenario, with only itunes on the macbook, the update is successful. Latest attempt was to erase HD, reinstall OS X, and only reinstall itunesin orde to test the update feature. I get message: '.device isn't eligble for requested rebuild.' I have worked with Apple store Genius bar staff 4 times with no sucess. With my 2 yr old macbook, I cannot update my recently purchased iphone 4 when an ipdate is available.