This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Thunderbird email from Gmail - where are the emails stored on the computer?

  • 3 replies
  • 0 have this problem
  • 21 views
  • Last reply by christ1

more options

I read at AskLeo that I could use Thunderbird with Gmail as a way to backup my Gmail emails to my computer. I then want to backup the Thunderbird folder using a backup program to save the emails to an external drive.

On Windows 10 Home, where do I find the emails that Thunderbird is downloading from Gmail? I recently installed Thunderbird 102.1.0 (64-bit) using IMAP and OAuth2 authentication.

I looked in C:\Users\USERNAME\AppData\Roaming\Thunderbird\Profiles There I see 2 folders with numbers and letters:  In the first folder (XXXXXXXX.default) I see only this file: times.json In the second folder (XXXXXXXX.default-release) are many files. One is called Mail. However, I don't see email further inside the Mail folder. 

Could the emails be in the ImapMail folder? If these are not the actual emails, what are they? C:\Users\USERNAME\AppData\Roaming\Thunderbird\Profiles\XXXXXXXX.default-release\ImapMail\imap.gmail.com

2) Is there a limit to the total number/size of emails that Thunderbird can store? My Gmail account is using 8 GB of storage. 

Thanks!

I read at [https://askleo.com/back-email-using-thunderbird/ AskLeo] that I could use Thunderbird with Gmail as a way to backup my Gmail emails to my computer. I then want to backup the Thunderbird folder using a backup program to save the emails to an external drive. On Windows 10 Home, where do I find the emails that Thunderbird is downloading from Gmail? I recently installed Thunderbird 102.1.0 (64-bit) using IMAP and OAuth2 authentication. I looked in '''C:\Users\USERNAME\AppData\Roaming\Thunderbird\Profiles''' There I see 2 folders with numbers and letters:  In the first folder (XXXXXXXX'''.default''') I see only this file: times.json In the second folder (XXXXXXXX'''.default-release''') are many files. One is called Mail. However, I don't see email further inside the Mail folder.  Could the emails be in the ImapMail folder? If these are not the actual emails, what are they? C:\Users\USERNAME\AppData\Roaming\Thunderbird\Profiles\XXXXXXXX.default-release\ImapMail\imap.gmail.com 2) Is there a limit to the total number/size of emails that Thunderbird can store? My Gmail account is using 8 GB of storage.  Thanks!

Modified by Lavendel

Chosen solution

Could the emails be in the ImapMail folder?

Yes, that's where they are. Note, mail files are the ones without a filename extension, e.g. like Inbox, or Sent.

Is there a limit to the total number/size of emails that Thunderbird can store? My Gmail account is using 8 GB of storage.

There is no one specific number/size limit for emails. As a general rule of thumb, don't let mail file like Inbox grow indefinitely. Keep Inbox as tidy as possible. Sent also tends to grow large over time. Therefore archiving may be a solution, to split it in yearly folders with a manageable size. https://support.mozilla.org/kb/archived-messages

Gmail has a folder called 'All Mail', which contains all messages of your account, which may not work well when antivirus want's to scan a 8 GB file every time it's being accessed. Unless you desperately need 'All Mail' you may want to unsubscribe from it.

In order to be used as backup, you'll have to download an offline copy of your messages, so that there actually is something to be backed up. In Thunderbird speak this is called 'synchronization' which can be turned on on a per folder basis. https://support.mozilla.org/kb/imap-synchronization

Read this answer in context 👍 1

All Replies (3)

more options

Chosen Solution

Could the emails be in the ImapMail folder?

Yes, that's where they are. Note, mail files are the ones without a filename extension, e.g. like Inbox, or Sent.

Is there a limit to the total number/size of emails that Thunderbird can store? My Gmail account is using 8 GB of storage.

There is no one specific number/size limit for emails. As a general rule of thumb, don't let mail file like Inbox grow indefinitely. Keep Inbox as tidy as possible. Sent also tends to grow large over time. Therefore archiving may be a solution, to split it in yearly folders with a manageable size. https://support.mozilla.org/kb/archived-messages

Gmail has a folder called 'All Mail', which contains all messages of your account, which may not work well when antivirus want's to scan a 8 GB file every time it's being accessed. Unless you desperately need 'All Mail' you may want to unsubscribe from it.

In order to be used as backup, you'll have to download an offline copy of your messages, so that there actually is something to be backed up. In Thunderbird speak this is called 'synchronization' which can be turned on on a per folder basis. https://support.mozilla.org/kb/imap-synchronization

more options

Thanks for your reply.

In the lower left corner of Thunderbird, it says "Downloading message 36182 of 40892 in Sent Mail." Does that mean the email is being downloaded from Gmail to Thunderbird? Or from Thunderbird to my computer?

In "Synchronization and Storage," I had this option already check-marked: "Keep messages for this account on this computer." So I guess these messages on my computer are the files without a filename extension, like you said.

In the ImapMail > imap.gmail.com folder, what are the .msf files?

more options
"Downloading message 36182 of 40892 in Sent Mail." Does that mean the email is being downloaded from Gmail to Thunderbird?

Yes.

In the ImapMail > imap.gmail.com folder, what are the .msf files?

They are index files containing information for each message about email status (read, replied, …), threads, indexing by gloda, etc.