This is the most effective way to prevent Thunderbird from fetching years of old messages while keeping recent emails available offline.
: Thunderbird will still download message headers (subject and sender) for all emails so you can see them in your list, but it won't download the full content until you click on them. 2. Limit Downloads by Message Size thunderbird limit email download
Can I limit messages to a recent time period? - Mozilla Support This is the most effective way to prevent
: Right-click your email account in the left pane and select Settings , or go to Tools > Account Settings . thunderbird limit email download