After having updated OS X to the latest version (currently version 10.10.4), you may find that while Mail will launch and display messages, it may not send or receive new ones. In some cases this problem is only in one direction, where you might be able to send messages but not receive them or perhaps receive messages but not be able to send them. These behaviors in Mail might seem a bit perplexing, but generally can be fixed with a few steps. Continue reading →