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MBOX files much smaller than indicated in TB

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paul2801
 
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Joined: September 10th, 2020, 1:15 am

Post Posted September 15th, 2020, 2:35 am

in order to make a backup of all my email I copied my whole profile folder on disk to an external drive. The online folders seemed to contain suspiciously little space compared to the local folders.
To investigate I studied the relation between what is shown in TB and what is stored on the file system. Now i think I know MBOX files, MSF and SBD files and the relation between them.

What I don't understand is the size of the online MBOX files. My Inbox contains 134 MB of messages (300 msgs) as shown in TB. Yet the corresponding MBOX file size is only 0.483 MB.
I tried to force a sync (File > Offline > Now download/sync) but the MBOX file stays much too small. Apparently most messages are not downloaded.

The same occurs with all other online folders I created. For instance, the folder 2020 (at same level as inbox) contains 32 MB of messages as shown in TB. Yet the mbox file only contains 67 kB while the MSF file (just headers!) contains 78 KB!

My account is a Gmail account. Don't know if this is relevant.

PS Last week I moved an online folder 2016 (43 MB) to Local folders. I would expect the original 2016 folder to be removed in TB. Instead, it still shows up but now the mbox file is empty!! The mbox file in local folders is OK.

It's all a mystery to me. I'm afraid I'm missing something. Any clarification more than welcome!

DanRaisch
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Post Posted September 15th, 2020, 4:09 am

From your post iHow is the account set up, as POP or IMAP? Tools->Account Settings->Server Settings->Server Type at the top right of the dialogue.
If that is the case, check the setting under Tools->Account Settings->Synchronization & Storage->Is "Keep messages for all folders for this account on this computer" checked?

tanstaafl
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Post Posted September 15th, 2020, 3:01 pm

I assume you're using a Gmail IMAP account since you mention File > Offline > Now download/sync

Do you have any settings that would limit whether a full message is downloaded to the mbox file? I'm thinking of the disk space settings in the account settings and using "MIME Parts On Demand" settings to control whether a attachment is downloaded before its opened.

What version (use help -> troubleshooting information, NOT help -> about Thunderbird to get that info as the latter forces a check for an update despite your settings) are you using?




http://kb.mozillazine.org/Entire_messag ... AP_message

paul2801
 
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Joined: September 10th, 2020, 1:15 am

Post Posted September 16th, 2020, 2:30 am

Sorry forgot to say it's an IMAP account (gmail.com)
@Danraisch: Yes, 'keep messages on this computer' is set.

@tanstaafl: I assumed the menu command Offline > Download/sync would download all messages but it doesn't.
Next checked the disk space settings. As far as I can remember left everything to default: sync most recent 30 days, don't download messages larger than 50 kB.
Changed settings to Sync all irrespective of age. TB immediately began downloading and the MBOX files are filling up nicely.

PS (maybe OOT) Is there a better way to make an email backup than copying the whole profile? Previously tried the addon Input-output tools NG but this copies MBOX files without change, thus does not contain full messages.

Many thanks for your clarifications, helped a lot.

tanstaafl
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Post Posted September 16th, 2020, 3:46 am

I don't think the problem was the ImportExportTools NG add-on, it has to live with whatever restrictions you impose due to settings.

http://kb.mozillazine.org/IMAP_backup has some other suggestions. IMAPSize might be a good choice because it backs up messages using .eml files and it does an incremental backup - it won't backup a message again if its already backed up.

The important files to backup are usually your mail, prefs.js file (settings), your address books, saved passwords if you use the password wizard (logins.json) and your calendar (if you have one - local.sqlite ). Everything else can either be re-created or re-installed.

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