There are several reasons Keychain does this. Often it's because a new account that you might have switched to does not have the same/correct paths to Keychain that it used to. For starters try changing the main login password of your account; if that doesn't do anything try this in terminal:
$ sudo touch login.keychain
$ codesign -vvv /Applications/Utilities/Keychain\ Access.app
If you get an error such as:
/Applications/Utilities/Keychain Access.app: code or signature modified
then:
$ codesign -vvv /Applications/Utilities/Keychain\ Access.app
which should give you the response:
/Applications/Utilities/Keychain Access.app: valid on disk
/Applications/Utilities/Keychain Access.app: satisfies its Designated Requirement
Reboot.
Not sure if this helps but been a mobile me user for a year now and this is my outlook 2007 settings:
Also worth noting I have seen in small print that iCloud will only work with Outlook 2007 & 2010
Account type: imap
Incoming mail server: mail.me.com
Outgoing mail server: smtp.me.com
- (I note that Apple's KB of this states: smtp.mail.me.com i.e. mine does not have "mail" in it).
User name: (_ _ _ _ _)@me.com (don't put in @me.com though)
Tick require logon using SPA
on advanced tab:
outgoing server tab
my outgoing server (SMTP) requires authentication: tick this
use same settings as my incoming mail server: click this
Advanced tab
Incoming server (IMAP): 993
Use following type of encrypted connection: SSL
Outgoing server (SMTP): 587
Use following type of encrypted connection: TLS
So far my account is still working but have not upgraded to iOS5 or iCloud yet as waiting for update to another program that I use to bypass iTunes for music importing.
Best Answer
I got a mail from Apple a time ago where they said that I could use x@icloud.com, x@me.com and x@mac.com with no difference. However, I can't find it right now.
Try send a mail to your @me.com and login to icloud.com with your @mac.com. Did you get the mail? Then, they're all the same account (and have the same passwords)! Else, I hope you did put in an alternative email when setting up your @me.com. Use iforgot and select 'send to alt email'. If you didn't, then you're probably a bit out of luck.
Good luck!