When I try to change mail account configurations setting, f.i. changing port number, SSL checkbox or username, OSX keeps resetting my entries to the old values. This happens 'live' while I try to change things. Sometimes even during typing a username, my entry is reset to the old username.
I takes multiple tries until finally my changes are not changed back to the old values and I can hit the save button.
I've tried removing all accounts and recreating the accounts. This helps for some time, but then the problem comes back again.