After an update, the Evolution email client on Ubuntu 14.04 LTS would not remember any passwords. Each time it tries to retrieve messages, it asks that passwords be entered. Even though the check box to Add the password to the key ring is clicked, it never stopped asking. It neither stored passwords in the key ring.
This issue appeared only after an update was applied. To resolve this issue, the following steps need to be done.
1. Exit Evolution
2. Remove the seahorse program by entering command below in a terminal window:
sudo apt-get purge seahorse <enter>
3. Restart the computer
After this, Evolution will not prompt for the passwords.
This was also described at this link https://bugs.launchpad.net/ubuntu/+source/evolution/+bug/1299604/comments/11.