This article explains how to remove old mail from a folder or an entire account automatically in Mozilla Thunderbird 68 or higher on Windows 10, 8, or 7; Mac OS X 10.9 or higher; and GNU/LINUX.

What to Know

  • For one folder, go to Folder Properties > Retention Policy > Delete messages more than __ days old > enter time > OK.For an entire account, go to Preferences > Account Settings > Delete all but the most recent __ messages > enter number > OK.

Remove Old Mail Automatically From a Folder

You can configure Thunderbird to delete old messages in every folder in Mozilla automatically. What is useful for the Trash folders is also great for RSS feeds, for example.

  • Right-click the desired folder.
  • Select Properties from the menu.
  • Go to the Retention Policy tab.
  • Make sure Use server defaults or Use my account settings are not checked.
  • Select either Delete all but the most recent __ messages (or Delete all but the last __ messages) or Delete messages more than __ days old.
  • Typically, make sure Always keep starred messages is checked; this allows for an easy way to preserve emails.
  • Enter the desired time or message count.
  • Keeping about 30 days or 900 messages in a Trash folder usually works fine. Even for something like your default inbox, 182 days (around 6 months) can work.
  • Select OK.

Remove Old Mail Automatically for an Entire Account

Set a default policy for an account where Mozilla Thunderbird deletes old emails across folders in the account.

Right-click the desired folder.

Select Properties from the menu.

Go to the Retention Policy tab.

Make sure Use server defaults or Use my account settings are not checked.

Select either Delete all but the most recent __ messages (or Delete all but the last __ messages) or Delete messages more than __ days old.

Typically, make sure Always keep starred messages is checked; this allows for an easy way to preserve emails.

Enter the desired time or message count.

Keeping about 30 days or 900 messages in a Trash folder usually works fine. Even for something like your default inbox, 182 days (around 6 months) can work.

Select OK.

  • Select Preferences > Account Settings from the Mozilla Thunderbird menu.
  • You can also select Tools > Account Settings (Windows, Mac) or Edit > Account Settings (Linux) from the menu.
  • For local folders and POP email accounts, go to the Disk Space category for the desired account (or Local Folders).
  • For IMAP email accounts, go to the Synchronization & Storage category for the desired account in the Account Settings window.
  • Make sure you checked Delete all but the most recent __ messages or Delete messages more than __ days old.
  • If prompted, select OK in the Confirm permanent, automatic deletion of messages dialog.
  • Click OK.

Keep in mind that messages you want to keep might inadvertently be deleted with this setting.

Select Preferences > Account Settings from the Mozilla Thunderbird menu.

You can also select Tools > Account Settings (Windows, Mac) or Edit > Account Settings (Linux) from the menu.

For local folders and POP email accounts, go to the Disk Space category for the desired account (or Local Folders).

For IMAP email accounts, go to the Synchronization & Storage category for the desired account in the Account Settings window.

Make sure you checked Delete all but the most recent __ messages or Delete messages more than __ days old.

If prompted, select OK in the Confirm permanent, automatic deletion of messages dialog.

Click OK.

Get the Latest Tech News Delivered Every Day