Mail not remembering iCloud password

Try File>Add Account and re-add your account. Worked for me.

This worked perfectly! Thanks so much!

If deleting then adding your account back doesn't work, go here:

http://www.wilmut.webspace.virginmedia.com/notes/icloudmail.html

I struggled with this problem for days until I followed these steps.

It would help others if you marked this question as 'answered.'

This from another thread:

So I found this and it works:

Open the Mail app. Go to Preferences. Click on the Accounts tab, and then the Advanced tab.

Look for the Authentication box. If you're having this problem, it will be set to "Password." Click on the box and select "Apple Token."

Apple uses Tokens as a secure way to access iCloud services without having to use your password, by providing your username and password to the app over an encrypted SSL connection.