Comment 33 for bug 255768

Same issue on Karmic with evolution, in my case all worked flawlessly until inadvertently clicking hibernate, from which my pc would not wake from and a hard reset to restart karmic, this was the start of the problem for me.

The relevant keys and their passwords for their mail accounts exist in seahorse until evolution is started, when intermittently either the key or sometimes just the password component are deleted from seahorse.