if not, give it a try.
The other alternative, somewhat drastic and will involve reconfiguring your Mail settings, is to trash the Mail preference file.
Do the permissions thing first
Mail has suddenly stopped responding to just about any action like new, reply, preferences etc. It will still receive new email but nothing much else.
When trying to access these actions, nothing happens - no window, nothing apart from a brief flash of "File" being highlighted. Most recent change has been to install latest OS security patch but it wasn't working before this anyway.
any thoughts anyone?