Fix Error Thunderbird Inbox is full and can’t hold any more messages

“Last week I got an error message like Alert! The folder Inbox is full and cannot hold any more messages. To make space for more messages, erase any old or unnecessary mail and compact the folder. I have deleted so many mails and reduces the size of inbox approximately half. However, surprisingly I received the same alert message once again the next day. This message comes to me for the very first time. My ISP proved to be unhelpful this time. I have consulted them and the solutions they have told me are useless. Even I have reduced the size of my Thunderbird inbox more at their suggestion, but nothing happened. In short, I have tried all the possible things to resolve Thunderbird inbox folder is full issue from deleting the emails to the un-installation of Thunderbird. Now, I am fed-up completely and finally want to know a method to resolve this issue as soon as possible. Can anyone help me out?”

Considering this query, we will go to discuss the method to resolve the issue completely.

Resolution of the Error Thunderbird Inbox Folder is Full

Deleting and compacting are the two major steps to get rid of this error.

Compacting

Whenever a message has been deleted from Thunderbird, it is only marked as erased or removed in the mail file. To delete it properly you need to compact the folder. Compacting of the folder is so necessary that if you do not compact the folder, it will create a problem for the user by getting bigger and bigger in size until or unless Thunderbird scratch its head. Users need to do compacting on regular basis in every email program. It can be on weekly basis as well. If done daily it can become a quick process. If not done regularly the user may face “Thunderbird Inbox folder is full” error again.

Deleting

Installing or Uninstalling will hardly do anything here, as the trouble is with the email files, which are unaffected by this. Therefore, along with compacting, the other solution is to delete the incorrect files. Although Thunderbird is unable to open the file which includes new emails, it allows email to be migrated to another folder in the local hierarchy of folders. All the emails can be transferred in bulk at once. Select the first email and hold the shift key until the selection of the last email. After this, drag it to the new folder. The chances are very less that this type of bulk migration causes a full condition. This is because the folders almost all the times consist of few deleted emails. Therefore, while a folder takes some time to copy, it will approximately always be successful.

Recycle bin will not be used by Windows when you delete the file. This means, that the file is large for the recycle bin to hold. The file, which is named as inbox can be renamed as well.

In an explorer, there is no need to delete the file simply rename it. This leads to the normal working of the application. However, it will not fix the problem for the files that are large. In addition, it is a quick fix that will get your email into flow once again.

Note: Make sure that the changed file appears with that name only in Thunderbird. This will not allow you to cut yourself off from the data of the file.

Moreover, in explorer, you can see that each file is attached to a file of the similar name with an extension i.e. MSF. These are basically the indexes files that are associated with the folder and should be deleted once the name of the file is changed or deleted. In case the absence of the file, Thunderbird will generate a new index. It will also keep away the indexing issues if they are erased.

Trace the file

• Firstly, copy all your emails to a new folder
• Then, go to the Tools menu and then choose Account Settings
• After this, select the Server Settings for the account or local folders in case it is a local folder
• Now, you can see a local directory on the right bottom of the screen. You need to click on Browse
• Now, a new window will open, in that window click on the Highlighted Entry followed by a click on Explore. As soon as this is done, windows explorer will open, which is located in the folder where the offending file is situated
• To proceed towards the completion, close Thunderbird by a click on Cancel on all the windows of Thunderbird that are open and then finally on X
• For inbox problem, erase the inbox and inbox MSF files. Substitute the name of the folder here that is causing the trouble.
• Now, restart the Thunderbird applications after the completion of all the steps.

Quick Alternative: Another alternative to solve this problem is to recover deleted data file using SysTools MBOX to PST Converter Tool that will help to recover data from MBOX File  & extract into PST File

Conclusion

The mentioned issue occurred by a limitation on the Windows platform in those files, which are huge in size (greater than 4 GB). The inbox or any of the folders in Thunderbird can exceed this size if not compacted or have many emails. Therefore, considering all these things we have discussed the problem of Thunderbird inbox folder is full along with the solution that will reduce the size of inbox approximately to half.