Mozilla Thunderbird question: what does "building summary file for inbox"

[shance]

mean?

I can't get my mail box to open until this "summary file" is built.

What is this "summary file"?

[BlueEyedSon]

1. google is you friend

that's usually who i ask when my software is on the fritz

[azureblue]

2. It;s a reference file

A list of the emails so Moz can select the proper one when you click on the name in the emails column.

[shance]

3. Why does it happen whenever I open Thunderbird?

It happens everytime I click on to check emails.