Some days ago I received an email from my business owner regarding an issue. She started with writing 'Hi my_name' then she described the issue, in response I wrote 'Hello her_name' and then I wrote the solution to the issue. She tried the solution and issue was resolved but she had a different issue now and she replied the same email saying 'My_name, another issues here...'. Now I was reluctant to reply like 'Her_name, here is the solution...' instead I replied like 'Hello her_name, here is the solution...' and this mail thread was growing and growing. Just after couple of hours all issues were resolved.
I realised that I was replying in mail thread by saying hello again and again because of the fact that she is the business owner but at the same time I was feeling like there were too much of hello every time.
What is ideal way to greet or address people in a rapidly growing email thread?