also if oyu use torrent for download the download checksum is checked while it "downloads".
mogaes, I followed your links, very usful, bookmarked. thank you
Thank you everyone for your help.
It is taking a while to nut things out.
Please consider this thread closed.
Then please mark this thread as solved: Tread tools (near top of the page) -> mark as solved.
Up date, the trouble was tracked down to "update manager". Afriend of a friend had similar trouble and did updates via command line. This bypassed "update manager" and the updates to 12.04.4 went textbook perfect.