How to Fix Thunderbird Inbox Full Error?
Tags: thunderbird, mboxtopst, mbox, outlook
Published: 2021-10-29 10:42:22

Many Thunderbird users have reported receiving an error message stating that there is no more space in the Inbox folder to store messages. Due to this, they’re unable to receive/send new emails and read emails in their Thunderbird mail account. In this post, we’ll discuss the reasons behind this issue and provide some effective solutions to fix this error.

##Reasons for Thunderbird Inbox Full Error

There are numerous reasons that may lead to the ‘Thunderbird Inbox Full’ error. Some of them are: 

* The server is no longer accepting new emails.
* You have configured multiple Thunderbird accounts that haven't been cleaned in a long time.
* Thunderbird mailbox folders have reached the 4 GB limit. 
* There’s an issue with your Thunderbird version or it’s not updated.

## Methods to Resolve the Error Thunderbird Inbox Folder is Full

Since this issue impacts your work, it needs a quick resolution. You can try the below-mentioned solutions to resolve the ‘Thunderbird Inbox Full’ error.

### 1. Compact Your Thunderbird Folders

If you delete a message from Mozilla Thunderbird, it is marked as erased or deleted from the email file. You must compact the folders to completely eliminate the files from Mozilla Thunderbird. If you do not choose to compact the folder, it will continue to grow and cause various issues. To compact the folders, right-click on a particular folder (say Thunderbird Inbox) and choose the **Compact now** option.

![Compact Your Thunderbird Folders](https://www.stellarinfo.com/blog/wp-content/uploads/2021/10/Compact-Your-Thunderbird-Folders.png)

### 2. Recreate Deleted Items Folder

When your trash/deleted items folder gets full, you can recreate that deleted items folder. Follow these steps:

* Open Thunderbird application.
* Click the three lines on the top-right and navigate to **Help > Troubleshooting Information** on the home screen.

![Troubleshooting Information](https://www.stellarinfo.com/blog/wp-content/uploads/2021/10/Troubleshooting-Information.png)

* In the new window, select the **Open Folder** option in the **Application Basics** section.
* Now, close your Thunderbird application.
* Open **File Explorer** and navigate to the **Mail** folder. 
* Choose the mailbox that displays Inbox Full error message.
* Locate the Trash folder and delete the **Trash.msf** file.
* Further, you can restart Thunderbird and create a new Trash folder. 

### 3. Update Your Thunderbird Application

If your Thunderbird application is not updated, it may also cause issues with emails. In such a case, you must update your Thunderbird application. Here’s how you can do so:

* Open Thunderbird application. 
* Go to the **Help** option and click About **Thunderbird**. 

![About Thunderbird](https://www.stellarinfo.com/blog/wp-content/uploads/2021/10/About-Thunderbird.png)

* Your Thunderbird will automatically check for the updates and start downloading the updates, if there are any

### 4. Delete Thunderbird Emails

You need to check the deleted items folder. Sometimes, the emails get deleted from your system, but still remain in the trash folder. However, before deleting the emails, you can turn on the option to keep the emails backup. To do this, follow these steps:
 
* Launch your **Thunderbird** application.
* Further, navigate to **Tools > Account Settings > Server Settings**.
* Now, tick the checkbox **‘Leave messages on the server’**.
* You can also select the number of days for which the message will remain visible on the server. Along with this, you can also tick the checkbox for **‘Until I delete them’**.
* Click OK to save the changes. 

Now, follow the two approaches mentioned below.

### Approach 1 - Move Inbox Emails to a New Folder

You can export the inbox emails to any other folder in your Thunderbird application. This can be done by selecting an email and pressing the Shift key to move an entire batch of the email. When it’s done, drag all the emails to a new folder. This will free up space from your inbox folder.

### Approach 2 - Directly Delete all the Emails

The inbox emails can be directly deleted from your local storage. If your Thunderbird is configured with a POP account, all your emails are saved in the local system. After deleting the emails, restart Thunderbird and see if the ‘Inbox is Full’ error is resolved. 

## An Alternative to Create Backup

You can create a backup of your emails by saving them in different formats. For this, you can use a professional MBOX converter tool, like [Stellar Converter for MBOX](https://www.stellarinfo.com/email-tools/mbox-to-pst-converter.php). This tool scans the MBOX file and saves the emails and other items in various file formats, such as PST, EML MSG, PDF, HTML, RTF etc., by maintaining 100% data integrity. 

## Conclusion

There are several reasons that may cause the ‘Thunderbird Inbox is Full’ error. To resolve this, you can update your Thunderbird application, use the compact option, or delete/move the inbox items to free up space. However, it is strongly recommended to have a backup of your emails before performing any actions to resolve the error.