Symptom: Upon login OS X Mavericks continuously prompts you for a Key chain password which does not match either your iCloud/iTunes credentials or your local login credentials.
* Go to Finder.
* On the Finder menu, click on “Go”, then on “Go to Folder”. A box should come up.
* On the box, type in “~/Library/Keychains/” and click on “Go”. It should lead you to the Keychains folder where you will find three items: (1) a folder with a name mixed with letters and numbers, (2) login.keychain, and (3) metadata.keychain.
* Delete the folder with a name mixed with letters and numbers.
* Restart your computer. Check to see if the problem has been solved.
Solution Source: http://forums.macrumors.com/showthread.php?t=1652089