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why does .thunderbird have nearly 1600 files?

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  • 1 has this problem
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  • Last reply by christ1

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(Fedora 29; Thunderbird 60.6.1) (background) Nearly every Thursday, I do an incremental back-up before doing my weekly patches and scans. To easily, simply back up all my events, tasks, and e-mail and calendar preferences, I include the .thunderbird directory in the incremental back-up. I notice that there are nearly 1600 files in the .thunderbird directory, and that that part of the back-up takes quite a while. I recently deleted almost all the events/tasks from my calendar for last year. That didn't help: the .thunderbird directory still has nearly 1600 files. Important note: I do not store any e-mail on my workstation.

(the question) What are those almost 1600 files?

Thank-you in advance. Bill.

(Fedora 29; Thunderbird 60.6.1) (background) Nearly every Thursday, I do an incremental back-up before doing my weekly patches and scans. To easily, simply back up all my events, tasks, and e-mail and calendar preferences, I include the .thunderbird directory in the incremental back-up. I notice that there are nearly 1600 files in the .thunderbird directory, and that that part of the back-up takes quite a while. I recently deleted almost all the events/tasks from my calendar for last year. That didn't help: the .thunderbird directory still has nearly 1600 files. Important note: I do not store any e-mail on my workstation. (the question) What are those almost 1600 files? Thank-you in advance. Bill.

All Replies (7)

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What are those almost 1600 files?

Well, it's your profile on your computer, so only you can tell.

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I am hoping for some guidance on how to intelligently and effectively determine what is causing there to be so many files in that directory tree, as opposed to me wild-guessing and groping through that directory tree over many hours trying to brute-force figure it out.

I've already eliminated the obvious: e-mail messages and calendar events/tasks. What in the profile and on my work station could cause there to be such a large number of files? I notice that this directory tree is gobbling up 105+ megabytes.

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You think you looking for guidance. You looking for information that is really only available to you and a developer with an intimate knowledge of all the data stored by Thunderbird and Firefox as a part of the core is lifted almost directly from Firefox. There are probably one or two of them, but I doubt they have time for your query. It is after all without any real basis other than curiosity.

Try this as a starting point. http://kb.mozillazine.org/Profile_folder_-_Thunderbird

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> You think you looking for guidance. [... snip ...] but I doubt they have time for your query.

I understand; I accept what you said.

> It is after all without any real basis other than curiosity.

Not correct. There is a real problem, and an real and practical purpose for what I'm asking and doing. But based on the first part of your post, I'll drop this.

> Try this as a starting point. http://kb.mozillazine.org/Profile_folder_-_Thunderbird

Thank-you, Matt. Informative and interesting; eliminates many sub-directories and files. But not enough.

Based on the first part of your post, I consider this closed.

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Is there a 'cache2' directory in your profile? If so, this tends to have a large no. of files. It doesn't need to be backed up.

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I did not think to look for a cache directory. Good idea. Thank-you. I used the Linux "tree" command to find out:


bash.3[~]: tree -ad .thunderbird/ | grep -i cache bash.4[~]: bash.4[~]:


So as best as I can see, the .thunderbird directory tree has no "cache2" subdirectory. Are you're actually referring to "[private]/.cache/thunderbird/1tfov4t1.default/cache2/", which has a subdirectory "entries" that currently contains 16682 files? I do not include anything from "[private]/.cache/" in my incremental back-ups.

Since opening this thread, I've determined that the problem is almost certainly "[private]/.thunderbird/1tfov4t1.default/saved-telemetry-pings" is the problem. I've submitted this bug: "https://bugzilla.mozilla.org/show_bug.cgi?id=1553884" to address the problem.

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Are you're actually referring to "[private]/.cache/thunderbird/1tfov4t1.default/cache2/"

Yes. Your cache2 directory is located outside of the actual profile directory. That's the way it's supposed to be.