That's a corrupt keychain, nothing to do with Adobe.  Happened to me after the Apple Lion upgrade with some applications.

First open up the Keychain app in the Utitilies folder (or hit cmd+space for spotlight and type "keychain" it will be first).  Then in the search box at the top of Keychain, type "SiteServer".  That will bring up the DW passwords.  If you don't know your passwords, open each up and write them down.  Once you know them, delete the records that came up from your search.  Then proceed to open DW.  All passwords will now be gone and you will have to go through your site's 1-by-1 and re-add the passwords.  The site definitions will still be in tact, only the passwords will have to be re-saved since DW uses the Apple keychain to store passwords and not the configuration files.  Close DW and re-open again, your passwords should be good to go.

ifv, i'd recommend creating another thread with your issue since it is not related to the original post of a password/keychain issue.

FYI, I am having the exact same issue. My problem ended up being the same, after fixing my connection issue with SnakEyez help yesterday, my login credentials refuse to stay saved. So, for now, I will be simply putting them in daily or leaving my computer on.

I have a hard time believing that it is simply an issue with keychain because of the steps you've went through and because not a single other app is having the issue. However, I will continue to follow your progress on the issue and hope you find what you're looking for.

I have not yet tried that, but I will soon. I noticed that even when I go to my lock screen the login credentials clear from the servers. In fact, I will go ahead and try creating a new account now, though I do not feel that would be a viable solution for long term.

I had actually tried creating a new account earlier due to some additional issues I am having with Mountain Lion permissions, so that didn't do anything.

No, when you look at the Keychain, it is set up correctly for the application, but somehow it's not getting back from the keychain to the application (like it did in Lion).  This is one of those cases where Apple will blame Adobe, and Adobe will balme Apple and a couple months down the line there will be two quiet updates that pass in the night so that everyone can save face.

I think, based on my regrettable experience upgrading to Mountain Lion, that Apple folks are scrambling right now, plugging holes in what has been a pretty ill-planned update (from my perspective, anyway).

Hello,

I had the same problem using Dreamweaver CS4 now that I have upgraded from Snow Leopard to Mountain Lion on my new 2012 iMac.  Luckily I had exported my definitions with user id and password, for my web sites.  I thought I would try just importing the exported site definitions and voila, it worked.  The user ID and password was saved wen I left Dreamweaver.

If you are currently not exporting your site definitions with user id and password, I strongly suggest you start.