Recently I was having a problem on a Windows 7 PC where Outlook 2013 would randomly ask me for a password to connect to an Exchange mailbox. No matter what I did, I couldn’t get it to remember the new password and ticking the checkbox to remember the password did nothing.
I used this command:
%windir%\system32\rundll32.exe keymgr.dll, KRShowKeyMgr
from a command prompt to open the “stored user names and Passwords” tool where I could edit the credential directly.