There is a programming flaw in Norton Security: if you back up to a flash drive, as I do every single week, the software does not recognize that a back-up has occurred, so all the warnings that you need to back up never re-set, even though, literally, a back-up may have just ended. This is really annoying and needs to be fixed. I have called support twice, un-installed, then installed the latest version of the product, but this error this occurs.
Do you have any other backup sets other than the one to the flash drive?