You would be hard-pressed to find a more stable e-mail client program than Microsoft Outlook. However, you can also make it produce error messages when it encounters a problem. The Outlook error code 0x8004060C is a good example. This error message is generated by Outlook when a PST file begins to exceed the storage limit.
Error message is:
“The `Microsoft Exchange Server – Send’ task reported an error (0x8004060C): `The message store has reached its maximum size. To reduce the amount of data in this message store, select some items that you no longer need and delete them permanently.”