Thunderbird

Gmail backup

• Follow this procedure:
  • Create a label in Gmail with all the data you want to backup / remove (for instance: Gmail 2016).
  • Label all the necessary messages with this label (the before:2016/01/01 filter may be useful). For a full year, "after: 2017/01/01 before:2018/01/01" (2017 example).
  • Launch Thunderbird, add your Gmail account via IMAP (if not already created). Get the previous backup files hosted in storage hard drives.
  • Select the created label, select all messages inside it and right click -> Get selected messages (so that Thunderbird downloads the actual content, not just the header). This will take a very long time. Sometimes "Get selected messages" is greyed out, which seems to mean that the messages are already downloaded (thus not necessary to do this step).
  • Put Thunderbird in offline mode (important).
  • Create a local folder (named for instance Gmail 2016), then choose all the selected messages inside the label, and Use "Copy the messages" to copy them to the local folder (this will take a very long time). It is recommended to also copy them to another folder containing all mails from Gmail (named for instance Gmail - Total Backup).
  • Once this is done, you can also easily create a file backup (of several GBs) of this folder just by copying 2 files (one without extension and one with .msf extension) on ~/.thunderbird/th3bio9j.default/Mail/Local Folders/ to somewhere else.
  • At last, put all messages on the Gmail label to the Trash and empty the trash.

• Note that if you move the messages with Thunderbird (to a local folder), they won't be deleted on Gmail. By default Gmail archives them which just means the "Inbox" label is removed.

Directories on disk

• Thunderbird directories are on ~/.thunderbird/th3bio9j.default/ (th3bio9j is the proile ID). Local folders are on ~/.thunderbird/th3bio9j.default/Mail/Local Folders/.

Plugins / Addons

The Import/Export tools is able to export Thunderbird mailboxes to different formats.