Today I upgraded what was a fresh install of DNN 4.4.1 (installed January 2007) to 4.5.1 in hopes of fixing an error I was getting when copying a page and all its modules.  After doing the upgrade, I was locked out of all portals on all accounts (even Super User accounts).  The error messages I received during login attempts made it look like I was using a bad password.  I tried a "forgot password" attempt but then received the error "There was an error retrieving your password. No password was sent."  I was pretty frustrated and about out of breath until I found this post:

http://www.dotnetnuke.com/Community/ForumsDotNetNuke/tabid/795/forumid/-1/threadid/55100/scope/posts/Default.aspx

All of our production portals are currently set for private Registration, so I had no way of performing the steps outlined in the post with my main install.  Fortunately I had an install on another server that had some open portals that I could Register a new user from.

I'll say, for folks who don't know SQL well, this would have been impossible and I hope there is something quirky about my installs (although the same behavior appeared on both my installations).  I'm pretty fortunate that I did this before my users started hitting their offices, otherwise I'dve had calls to deal with too.  Resetting the passwords for all the users generated enough questions as it was.  This leads me to another issue:  inability for successfully logged-in Super User to change passwords for users.  Every time I tried to change a password for someone, I received a "A critical error has occurred.  Bad Data."  My only recourse was to reset the password and have the user go through the motions.  I doubt that any of these are the intended behaviors.

Another issue I'm facing is with the caching provider.  When I installed 4.5.1, before I noticed the login problem I was amazed at how fast the new installation reacted on my system.  I imagine this is due to some better caching, but I noticed a problem when creating a new page as a copy of an existing page.  When copying, I also made copies of all the modules on the page.  After editing the newly created page, the display of the old page came up the exact same (as if I'd copied references, not new instances of the modules).  I again started sweating bullets because I modified *a lot* of text in a TEXT/HTML module on the new page, but fortunately after looking in the database I saw that all was still OK, at least somewhere in the server's memory.  I shut caching off and amazingly everything came up fine but was extremely slow.  Since I knew the behavior now I turned caching back on because I needed the performance boost and now I just ignore the problem, hoping the users aren't seeing enough to make them freak out.

Maybe everyone expects this type of behavior in caching...unfortunately if that's the way it is we'll have to figure something else out in the long run, as I need to hand off my duties on the portals to folks who are less savvy.

From what I can see there are a ton of great things in 4.5.1 as well.  Thanks to all for the tireless work.