Unable To Write To Mailbox – Thunderbird

Thunderbird updated and then on one of my Gmail accounts I kept getting an error message saying, “Unable to write the email to the mailbox. Make sure the system allows you write privileges, and you have enough disk space to copy the mailbox.” Then I would get only one email downloading over and over – in one instance, 121 times.

I have three Gmail accounts, and only one account was affected. Online support suggested, Not enough disk space or insufficient privileges. Corrupted folders. Antivirus. The easiest to check was the Antivirus, in my case, Avast.

Disable Avast

So I disabled it temporarily. Right-click on the icon in the system tray (down by the clock), click on “Avast shields control” and then “Disable for 10 minutes”. Then I right-clicked on the account in question in Thunderbird, clicked on “Get messages”, and it worked.

Exclude Folder

I couldn’t find any controls in Avast for email scanning, there is an “Email Guardian” component but is only available to premium users. So what I have to do is to exclude this folder from being scanned by Avast.

Open Avast. Click on the Menu option (top right-hand corner) and then click on “Settings”.

Then down the left-hand side click on “Exceptions”.

Then click on the green “Add Exception” button.

Just click on “Next” on the following screens till you get to the “I Understand Risks” button. Click on it.

Now in the “Add exception” box, click on “Browse”.

In my case, I had to navigate to: C:\Users\Terry\AppData\Roaming\Thunderbird\Profiles\t0g983m6.default\Mail\

I have three Gmail accounts. I assumed the first one was the one I was looking for and put a checkmark in the box, then clicked on OK.

Back to the “Add exception” box. Click on the green ”Add exception” button.

Then I went back to Thunderbird and again clicked on “get messages” for that account and no error message. One more test. Restart Thunderbird. When it opened, no error message, and my emails were downloading properly again.

So, until something else updates and screws something else up…

For more troubleshooting articles on Thunderbird

For more troubleshooting articles on Avast

7 thoughts on “Unable To Write To Mailbox – Thunderbird”

  1. Getting similar message almost every time I get email, only the FOLDER name and account changes.

    The messages could not be filtered to folder ‘Slickdeals on Irv Gmail’ because writing to folder failed. Verify that you have enough disk space, and that you have write privileges to the file system, then try again.

    If I use TOOLS to run the Filters on all of my accounts, they all work fine and some have messages moved to the suspect folder.

    This started a few versions ago.

    1. Terry Hollett

      Have you tried excluding your entire profile folder? If you don’t use Avast, do a little research online to find out how to exclude folders from scanning with your brand of antivirus.

  2. I’ve got McAfee Live Safe, only allows it seems is specific files.
    Mail is in many different ones, but are you suggesting it is MY A/V that is causing the problems? Never did so for years, and only since the last few months of TB releases?

    1. Terry Hollett

      It’s possible. This is the first time I had this problem. They seemed to have changed something running in the background that was tripping up the scanners. Hopefully, future updates will fix this issue.

      1. Not having much luck with McAfee’s Real-Time paused and taking in email… it never failed. However, I can’t tell when it will?

        About 80% of the time it will not fail? Like today, none so far with it on?

        There was an update to TB today, 115.5.2 (64-bit), but I don’t know if this has anything to do with it not failing?

  3. Terry, I don’t know what it is, but it can’t be the A/V’s I feel. Too many happen, never pointing to the same folder either.

    I’m not even sure that the Folder was NOT written too? A few times running the FILTERS on the INBOX doesn’t seem to move anything? I watch the counts on the left side box of folders, and the Inbox doesn’t decrease on the Inbox or increase on the folder, but sometimes it does?

    I sort of suspect some timing issue of writing. Maybe too many threads trying to write to the same folder at once?

    I still can’t track it down though. To rule out the A/V though I will suspend it before bringing in the mail and see if I still get the error. However, even if I do not, and if it were A/V caused, I’d think the problem would be TB’s trying to write to a folder it did not have open to write too and should have handled an open error better (or the write one).

    Well, I did stop McAfee’s Real Time protection and got the mail, no errors, but it was a short tranch of emails. I’ll try later with a larger one, but I’m not sure when this happens, so I can’t tell if it does help, the only way to tell if it were a real TB problem would be if I did get the error but no way to predict when I get it, it doesn’t even happen every day normally?

  4. Well, SOMETHING has changed?

    Now I get on almost every time I bring in email I get an ERROR that the INBOX had a problem (usually my first account) and it stops bringing it in going onto my other 2 accounts without an error.

    Once completed, I just GET MAIL again, and it brings in the rest for the first account without a problem?


Leave a Comment

Your email address will not be published. Required fields are marked *

Exit mobile version


Get great content like this delivered to your inbox!

It's free, convenient, and delivered right to your inbox! We do not spam and we will not share your address. Period!