If you are facing trouble in writing or composing emails at repeated intervals, also encountering annoying messages can’t write email in mailbox in Thunderbird? Trust me if I say that you are not alone. Most of the Thunderbird users face the same issue when it won’t let them write a message in the mailbox. In this article, we will cover why it happens, and what you can do to fix the issue ofn’t sending emails in Thunderbird, and we will let you know some helpful Tools, such as SysTools MBOX to PST Converter, that will help you in converting or migrating the mail data if the issue still persists. So let’s dig in
Why does the “ Thunderbird Email Write Error” Occur
I will let you know that there are several reasons why you might face a “Thunderbird email write error”. Below are some common causes:
- Sometimes the Mailbox is corrupted or locked by another process, so you can’t write in mailbox in Thunderbird.
- File system permissions or disk storage: Some of the folders don’t give permission to write where Thunderbird stores mail.
- If the profile or folder is exhausted, or the size or file limit is exceeded, then they need to be compacted to repair.
- Sometimes the add-ons or antivirus software cause problems in writing in the mailbox.
- If there is a small glitch in account settings, then the problem also occurs in writing.
The first step is to identify the cause, then we are able to fix can’t send email in Thunderbird.
Troubleshooting to Resolve “ Can’t Write Email in Mailbox in Thunderbird”
# 1. Check the folder integrity and permissions
First things first, check that Thunderbird has permission to write into its folder. Simply click on Windows, right-click the profile folder, and check that your user account has write access. If you are using Linux or macOS, check that the folder is not read-only. After that, check if the file is locked or the folder is being synced by another tool like cloud sync. If you see it, immediately disable or pause that. Decrease the size of your folders in Thunderbird by going to the file, then compacting folders to reduce the size and free locks.
# 2. The mailbox file needs to be repaired or recreated
The reason you are seeing the Thunderbird email write error because the mailbox file is corrupted. You can check and resolve it by following the steps below:
- Immediately close Thunderbird
- Locate the mail folder in your profile, for example inbox with no extensions or .msf index file.
- Delete the .msf index file ( Thunderbird automatically rebuilds it)
- You need to rename the corrupted mailbox file to something else and create a new empty one with the same name. Then restart Thunderbird; It may recreate it, or you can move mails in. Most of the time, these steps Fix can’t send email in Thunderbird
Advance Insights When the Normal steps Don’t help Fixing Can’t Write Email in Mailbox in Thunderbird
# 1. Safe-mode and disabling extensions
Due to the interference of some third-party add-on or antivirus extension, the issue occurs. Put Thunderbird in safe mode; you need to hold the Shift key while starting in Windows, or via help restart with add-ons disabled. Check if the error disappears in safe mode, and if it does, then you are well aware of the culprit. Disable them one by one until you identify the one causing the can’t write email in mailbox in Thunderbird error.
# 2. Consider migrating the mailbox to a more reliable format
If the issue still persists despite all fixes, then it might be time to migrate your mailbox. For example, convert your local Thunderbird mailbox to another format or archive old emails. For this, we have a tool mentioned above which helps you in exporting your Thunderbird mailbox into a PST file for Microsoft Outlook, which is more reliable and stable, and supports a better workflow. After the data gets migrated, you can create a fresh Thunderbird profile with which you can avoid the repeated write errors.
# 3. Take a backup and clean up large or old folders
It usually happens with the large mailbox, as it can slow down folder operations and cause write locks and failures. Make sure to go through old folders, archive older messages to an external file, or convert them and remove them from the active mailbox.
Compacting the data size helps Thunderbird write more reliably and helps you avoid Thunderbird email write error.
Use MBOX to PST/ Thunderbird Converter Tool to avoid Thunderbird Email Write Error
As we discussed above that if your mailbox shows the same error despite doing repairs, compacting, checking permissions, and disabling add-ons, this is a sign of deeper corruption, incompatible format, and the can’t write email in mailbox in Thunderbird issue still persist. After all that, the only option that is left is migrating or converting using a dedicated converter like SysTools MBPOX to PST, which supports Thunderbird profile, giving you way more options to:
- Export your mailbox into PST or other formats, preserving folder hierarchy, attachments, and metadata.
- You can clean up the active mailbox and start fresh, while still retaining your archive safely.
- You can change the client if Thunderbird continues to misbehave.
Preventive Tips
Once you have applied all the fixes we have shared above, keep an eye on your account for a day or two.
- Try to write and send emails to ensure that can’t write in mailbox in Thunderbird error still persists.
- Monitor the mailbox size and growth
- Try to use auto-archive or backup to avoid the mailbox growing unbounded.
- Always use an updated version of Thunderbird and check your antivirus or syncing tools for interference.
Final Thoughts
Facing the can’t write email in mailbox issue in Thunderbird can be a big problem in your workflow, but once you know the reason behind it and get the right approach to deal with it, starting from permissions and folder integrity, going through extensions and larger-mailbox checks, and finally resorting to migration tools, you can quickly resolve it. For any reason, if all the fixes fail to resolve it, then the only option left is using a professional converter like SysTools Thunderbird to PST converter gives you the privilege to retain your email data while allowing you to bulk a more stable mailbox environment. By doing this, you will be back to writing and sending emails smoothly in no time.