[Joe Forster/STA]

Some Symantec software is complaining (or it's the one that got crashed?!). Some files on your backup copy might be damaged/unreadable/hard to read. You might want to compare the original with the backup copy: copy all the files from the original into an empty directory and compare it recursively with the files on the backup copy (e.g. FAR Manager and Total Commander both have such a recursive compare function). If there's a mismatch or the reading of the backup copy slows down, try making another backup copy and this time read the original and write the backup copy at a lower speed. Good luck!