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Permanently delete your mails on Thunderbird

A popular e-mail client like Mozilla Thunderbird stores all the mails in dedicated areas if they are deleted. Even mails that have been deleted from the Recycle Bin or Trash, will have left a trail behind. For safety & security reasons, it is best that the mails be permanently deleted. This can be done through a manual intervention: one has to go to Compress Files under File option. This needs to be performed for each account you have. The best way is to configure Thunderbird software automatically to compress the files which will ultimately save some space in the disk Hard Disk.


When you are deleting mails even when emptying the bin, they are not completely deleted. Thunderbird keeps these mails in a file.

Here we will learn how to permanently delete these mails or messages:


There are two solutions:


  • To permanently delete your mails/messages, go to "File" then "Compress files".
  • This will erase all messages in the folder or the selected account. This has to be done several times if you have multiple accounts.
  • So you can compress all the files at a time using CompactAllFolders (Extension) .


  • It is also possible to configure Thunderbird to automatically compress all the files so at least it will save some space.
  • To do this, open the Tools menu> Options (or Edit> Preferences), then in the "Advanced" category, open the "Network and Disk Space."
  • Check the "Compact folders when it saves at least ... KB" and fill in the field with the value of your choice (a short message is about 1KB).

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