Iphoto 6 to iphoto 11 HELP

Question

I am moving from a computer running Tiger to one running Mountain Lion. I was able to import my iPHoto library, but it loaded a whole bunch of duplicate photos, events with  just one photo in them, and NONE of my comments which is what I was using to categorize my photos, now I have about 9,000 random photos with no way to identify them.  What can I do???

Answer 1

Follow-up on this year-old thread.  Much appreciate the help around here, but it's interesting how self-assured (even smug) responders can be to those who post questions!
I just made the transition from Snow Leopard to Mountain Lion.  Followed what was so *categorically* asserted as the way of doing the photo transfer (supposedly simply copy over the iPhoto Library to the new computer). 
Well, guess what?  I now have two iPhoto libraries-- and it still opens up the Mountain Lion new one that has in intitial photo I saved the other day.  I think that you helpful souls are ignoring the many compounding variables!
For example, copying the library doesn't automatically replace one with the other (smart, actually!) and when it opens it doesn't simply use the old.  Nor did it give me a prompt as to which one I wanted to use! 
So, I thought a ste-by-step guide by someone who went through this would help other users in the same situation (as opposed to smart, helpful, yet glib, responses ).   (Sorry, but it's a pet peeve of mine that informed, smart people are all too often wrong, making sweeping statements, and even, not here, put down the questioners.  At the same time, I much appreciate the posts in this thread as they provided the general approach of what to do.)
You have to:
1.  Move the current iPhoto library OUT of the Pictures folder and to the desktop. 
2.  Put the old iPhoto library into the Pictures folder.
3.  Launch iPhoto.
4.  it will then prompt you as to which library you want to use. 
It's a confusing dialog box as you're being asked to choose between two files both of which are titled "iPhoto Library".   However, it does show the path to the file, so choose the one that's in the Pictures folder and NOT on the desktop.
5.  It will then give you an alert that your old iPhoto Library was created by a different version of iPhoto and ask if you want to upgrade the library.
I clicked OK.
I'm now timing it.  The dialog box says, "Now writing new iPhoto library data."  It's a 29 gb library, so it'll be interesting to see just how long this takes...
Wow!  Done in two minutes!
Note:  I moved the ML's installed library to the desktop, but I'll wager renaming it or deleting it would work as well-- don't do that, though, unless you are sure that it has no photos in it or none that you want to save.
Of course, now I have to search for information on reducing the size of an iPhoto library!  In normal use, I believe it's best to choose the option "Keep originals" or whatever it is now and copy the photos into the library. 
But 29 gb??!!!