Initial backup v 4.3.8 failed after 99% with code 97 (internal error)

Newbie who just downloaded the Comodo v 4.3.8 yesterday to back up my 64-bit Vista Home Premium SP2 DELL PC with RAID 1. It has MS Security Essentials running. Started the initial backup then immediately aborted it to try & figure out where it would back up to. Changed settings to back it up to a recently-purchased and working 2TB external hard drive with 1.8TB available space. Restarted initial backup and it ran for five+ hours before quitting at 99%. The last two lines of the log on screen were “Error reading from disk” and “Backup failed with code 97 (Internal Error)” There is nothing created on the external drive. I’ve used the new hard drive without problems and have had no indication of any problem with my internal mirrored 1TB drives which are less than 40% full. I’ve searched the board without success. I don’t know if the mirrored drives are an issue here or if I should doing anything special for Comodo settings with RAID. Any thoughts as to the cause of the error before I just try it again? Screen shot is attached. Thanks for any help for getting this long-time task off my to-do list!

UPDATE: Ran a test on another PC with RAID 1 and it ran fine so I guess the RAID is not the problem. Ran it again on the original PC, after closing down some typical background programs, with the same result as before. So I’m out of ideas. It takes over 5 hours to run so it’s not easy to troubleshoot.

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