See the Number of Messages in the Mozilla Thunderbird Folder List
To display the number of emails (both unread and in toto) for each folder in the Mozilla Thunderbird folder list:
- In Mozilla Thunderbird 3 and later:
- Make sure the Extra Folder Columns add-on is installed.
- In Mozilla Thunderbird 1 and 2:
- Select Tool | Options… (Windows), Edit | Preferences (Linux) or Thunderbird | Preferences… (Mac) from the menu in Mozilla Thunderbird.
- Go to the Advanced category.
- Open the General tab.
- Make sure Show expanded columns in the folder pane is checked.
- Close the configuration dialog.
- Click the table icon in the folder pane (next to the Name header).
- Click Unread, Total and Size so that a checkbox appears next to all the columns you want to see.
(Updated October 2012)