A quick search on google turned up this link:Outlook passwords
After upgrading from Office 2000 to Office XP, Outlook no longer saves my passwords for my email accounts.
I have it checked "Save this password in your password list" and also have "Remember Password" selected under Account Properties. Outlook only saves the password for that session of Outlook. When I close and reopen Outlook, I'm asked for my password, ("Save this password in your password list" is now unchecked). When I check the account properties "Remember Password" is still selected, but the password field is empty.
I've tried deleting and recreating the accounts, it doesn't solve the problem.
If I had just one email account it wouldn't matter, but I have a few.
After a lot of searching, I found out that "Protected Storage" service was disabled. This was my problem.