It looks like we've gotten
two different
reports of the first issue in the last couple of years. (It appears to predate Mountain Lion in at least some circumstances, in other words.)
It's possible that the Sandbox is blocking our attempt to talk to Mail for some reason, maybe due to the Sandbox. We'll need to investigate more to be sure.
Regarding the latter issue, and again, I'm really just guessing, but one possibility here would be be a keychain issue.
It's
possible that running the "Keychain First Aid" option in the Keychain Access utility will help here, but if it doesn't, please
email our support ninjas so we can investigate this with you.
(Emailing us is most helpful because we can gather console messages and other info that isn't very forum-friendly for a variety of reasons.)