Final answer:
Garth should start by identifying the problem and potential solutions before promptly and honestly communicating with the client, offering empathy and a plan to address the issue.
Step-by-step explanation:
When Garth must send a bad-news message to a client about being unable to meet a delivery deadline, the first step he should take is to identify the problem clearly and consider possible solutions or alternatives. After this assessment, Garth should communicate with the client promptly, being honest about the situation but also diplomatic and solution-oriented. It's important for Garth to craft a message that is not only clear and direct but also empathetic to the client's potential disappointment and offers a plan to mitigate the issues caused by the missed deadline.
Additionally, Garth should prefer using a personalized communication method, whether through email or a phone call, to ensure the message is conveyed with the appropriate level of professionalism and care.