How to check for corrupted files on imac

HOW TO CHECK FOR CORRUPTED FILES ON IMAC UPDATE

When I just now searched for mozy, all I get is. I had tried Mozy on this imac a long time ago and stopped using it, and I thought I had deleted it. Tomorrow I will call applecare about this, but in the meantime, if anyone out there has a clue, I'm much obliged. Furthermore, this macbook is still under AppleCare, yet that does not seem to mean anything to the Genius Bar. So this bad file likely was transferred to the macbook in that initial set up transfer.

HOW TO CHECK FOR CORRUPTED FILES ON IMAC UPDATE

During one of those visits, Genius suggested trying to do just the update of my iphone 4 from the macbook, and that is when we discovered the macbook had the same problem. I have been back to the Apple Genius bar 5 times since then with this problem. I purchased the iphone 4 in Sep 2010 and first tried an update in Nov 2010, which failed. When we bought the macbook, we bought one to one and had the Apple store do a complete transfer from the imac to the macbook in its first time set up. 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) 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.

How to check for corrupted files on imac