Stop typing and pick up the phone
Past the third round of an email-thread, a five-minute call ends what emails will not.
There is a point in every email exchange where the format stops helping. Usually it is past the third reply, when both sides are clarifying rather than deciding, and each message is getting longer.
Call instead. Five minutes on the phone resolves what four more emails will not, and you get tone, which is where most of the misunderstanding was living. If you are at the client, stop by their desk and talk it out in person.
Three signals that it is time:
• The thread has three or more rounds and no decision has been reached.
• Somebody has misread something. Once that happens, the written channel is now working against you.
• The topic is sensitive. Anything involving disagreement, disappointment or a mistake goes better spoken and worse written, and it also stops living in an archive.
There is a natural resistance to solving something over the phone. The email feels easier, cleaner, and less effort. But you are paid for the effort and to get it done. So Pick up the phone and get it done.
Important: After the call, send a short written summary: what was agreed, who does what, by when. Otherwise, you will have no accountability and nothing to refer back to, if the tasks don't get done.
If the thread is on its third round, it is a phone call.