signon-ui continually pops up "Enter your credentials" after upgrade to 14.04 Trusty Tahr

This bug is being experienced by myself and at least 1 other person (who posted the question on askubuntu.com). So I assume there must be more people who have seen this bug too.

Added "link to existing bug" that I created because I am also getting this. The askubuntu question is at:
http://askubuntu.com/questions/451245/signon-ui-enter-your-credentials-dialog-on-desktop

Please go to the bug page and click on the link that asks if that bug affects you to increase the number of people that confirm the bug and perhaps it will get fixed sooner.

Myself and one other person has found a Yahoo account was causing the issue.

My answer below -

I have also found a fix for this. In my case, it was also a Yahoo account in Online Accounts which was the culprit.

Symptoms of a faulty Yahoo account in Online Accounts manifest as the following: When you go to System Settings > Online Accounts, click on your Yahoo Account in left column, then click on "Edit Options", there will be NO information displayed - window will be blank instead of the expected username & password fields.

To fix a faulty Yahoo account in Online Accounts you need to delete the account and re-add it: Go to System Settings > Online Accounts, click your Yahoo Account in left column, click "Remove Account", then click "+ Add account..." The username & password fields will display as expected and you can fill out your account info. Congratulations, the "Enter your credentials" popup is now gone when you reboot.