thanks a lot, it's just what i've done just before nevertheless i do not understand why the initial loading is not done at the right level !!!!
just a complementary question : How do i do to have a short view on these files on my MAC because CR2 are not always recognized ...?
The initial installer is for 6.0 and is an 800+MB file. Unlike previous versions of LR, the upgrades to each minor version (.1, .2, etc) are merely patches to this initial install so are much smaller and quicker to download for those who have been on LR 6/CC since the beginning.
So to answer your question, the install/patch process is more efficient for those who've been using LR all along, and Adobe has chosen not to make a separate installer for each version just so anyone who hasn't been using LR 6/CC since the first version has a quicker path.