"Unable to write email to the mailbox"

User Help for Mozilla Thunderbird

User avatar
Posts: 17
Joined: December 27th, 2006, 10:27 am

Post Posted May 28th, 2017, 11:52 am

I have a very strange problem - maybe you could help me out.

I am using Thunderbird on 2 computers, both Thunderbird versions using exactly the same setup: occasionally I'm copying the profile directory from my main, standalone PC to the notebook computer (to have the most accurate email reply status information etc. there).
Now I've bought a new notebook computer to replace the old one - and on this new one, I now regularly receive popup messages like

"There was an error downloading the following message:
From: "Joan Brewster" <>
Subject: ***SPAM*** Re: C*alis Daily is worthy to try and to love.
This message may contain a virus or there is not enough disk space. Skip this message?"

When I click "ok", the message is skipped, otherwise I get:
"Error with account XY
Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox."

Note that the problem is actually NOT related to spam / a virus!
I get these popups even for normal emails of only a few lines and containing regular text.
And I seem to get them on a 'random' basis, i.o.w., some emails are processed without any problems, while others are not.

I am really curios about why exactly the same files (Thunderbird data directories) give me those errors on my new notebook, but no problems at all on my regular PC. Could it be related to the fact that my notebook only runs with a SSD disk? Also, the Notebook runs Win10, while the desktop PC is running Win 7.

It may be worth to mention that only 1 of my mail accounts (using a POP setup) is affected. It is a catchall account, meaning that sometimes when I didn't run Thunderbird for a few hours, 100-200 emails may have to be processed, many of which are to be moved to the Junk folder. Maybe it's a sync issue that is triggered in combination with fast (my SSD) harddisks?

thanks ,r.


User avatar
Posts: 116118
Joined: September 23rd, 2004, 8:57 pm
Location: Somewhere on the right coast

Post Posted May 28th, 2017, 5:41 pm

Moving to Thunderbird Support.

Are you running the same security software on both systems?
Is the new laptop now running a very recent copy of the data from the stand alone PC or has it been receiving messages directly from the server?
Also see this article -- ... he_mailbox


User avatar
Posts: 17
Joined: December 27th, 2006, 10:27 am

Post Posted June 7th, 2017, 9:55 am

Hi and thanks for your reply!

on my Win7 computer (where I never have this problem), it's MS Security Essentials,
on my Win10 computer (where I get these errors), it's the standard 'Windows Defender'.

On both computers, Mozilla's data files are on a SSD partition.

The KB hints:
I don't think the folder is corrupt, as I regularly sync the files between the computers. That has never been a problem. Compacting the folders also doesn't make a difference.
EncFS: nope (also in Win10, file compression or encryption isn't activated)
The old bug: I don't think this applies, because I'm using exactly the same version of TB and of the configuration files on both computers, so there's no difference in how they access the server.

My best guess is that it's either something about the SSD or some Windows 10 setting that causes the problems. :-(

Return to Thunderbird Support

Who is online

Users browsing this forum: No registered users and 4 guests