Using comodo back up versions 3.0-4.2.15 i have same problem.
Size of drive is not problem, AVG isnt either.
I have 2 hard drives i can make a clone copy to and all is fine, all other drives when i do a clone copy and boot from the copy windows 7 tells me there erros on disk that its checking for consistency.
Now once i let it run chkdsk which it does on its own the clone copy seems fine and boots ok.
Only think i can possible think of is maybe the drives were originally formatted LBA or nonLBA?