Fix Error Thunderbird Inbox is Full & Can’t Hold More Messages

Admin | September 29th, 2017 | Thunderbird

In this article we are going to talk about the Thunderbird Inbox is Full & Can’t Hold More Messages error. Mozilla Thunderbird end user’s scenarios related this errors in details, Get relevant solution for the same.

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

Thunderbird User’s Scenarios

“When I was working on Mozilla Thunderbird, that time I realized that my Thunderbird application has 2 Inboxes for a single account. The storage location of one is C:|Users\…\AppData\Roaming\Thunderbird\Profiles\5ty7hjutyg.All\Mail. The other one is on my other drive where Thunderbird actually stores my mails. I deleted the mails of both inbox.msf and inbox folder from both the storage locations. Still, I am receiving the same error and can’t able to access Thunderbird email files. Is there any possible solution to resolve the error Thunderbird Inbox is full and can’t hold any more messages problem? Can anyone help me out how to deal with the turbulence? Thanks.”

“A few days back, while working on Mozilla Thunderbird, I received an error message like Alert! Inbox Folder is full & cannot hold more messages. In addition to it, it even blinked as to make space for more messages, delete or erase few unnecessary mails and compact folder. I followed the same and empty my internal storage of Mozilla Thunderbird. Everything went smooth but after 3 days it started showing the error again. I consulted my Internet Service Provider but, it was of no use as no one came to resolve the issue. I tried many things from uninstalling Thunderbird to deleting the things in mass. Still, it was of no use. So, I am in deep trouble and want to get rid of it. If anyone possesses a solution please help me out and all the leads shall be highly appreciated. Thanks in advance.”

These two queries brought me in a state of procrastination and I kept on searching regarding the topic in detail. I have really contended when I got solution to the problem. So, I have decided to provide the complete information on it. I hope it will be helpful in many ways.

Solving the Error: Thunderbird Inbox is Full & Can’t Hold More Messages

There is two main hotfix through which the error can be solved.


Sometimes, Installation and uninstalling hardly creates any sense. The problem arises with mail files and for it, no need of installing/uninstalling occurs. So, the best possible solution to solve this error Thunderbird inbox is full is deletion of incorrect files. Though, Thunderbird is not able to open files which comprise of new mails. It can even be exported to any other folder in the list. The emails can be moved in batch in a single attempt. All the user needs to do is press shift key from first mail to the last one. Once it is completed, drag it to a new folder. In such circumstances, probability of full resolution of problem is very low. This happens because folders comprise of few deleted mails. Henceforth, if a folder takes time to copy the emails, in that case, the chances are that it will be successful. Windows will not make use of Recycle bin in deleting an email file. It implies that the file is very big to be handled by recycle bin. Even the file which holds Inbox as name can be renamed too. If you are using Explorer, then, in that case, there is no necessity of deleting the emails only you need to rename it. It makes the application work in a normal way. But, this will not work for the large sized files It can be treated as a quick fix to get the mails in flow again.

Note: Ensure that the changed file occurs in the name of Thunderbird only. It does not cut you from file data.

Users can even find out that in Explorer, that each file is inclined to file with a similar name having extension as MSF. The files are index file that is inclined with folders and can be deleted if the name of file is deleted or changed. Mozilla Thunderbird creates new index file. It also keeps separating the index issues if they are deleted.


If a single message has been deleted from Mozilla Thunderbird, they are retained as erased or are deleted from the email file. For completely deleting the files from Mozilla Thunderbird, you need to compact the folders. Compacting of folders is a necessary task to do. If you will not compact the folder, it will keep on increasing and can lead to multiple problems. The users should compact folders on the regular basis of all the mailing programs. To ease the efforts, it can be done on weekly basis. But, if a user makes it a habit the work will become a quick process. If it is not done at all, the users will come across the Thunderbird Inbox is Full Error again.

Tracing Files

  • Copy emails to a new folder
  • Go to Tools >> Choose Account Settings
  • Select Server Settings or Local Folders
  • Browse for the data to get details of local directory from right side
  • Open a New Window and click on Highlighted Entries by clicking on Explorer. After the process is completed, Explorer will open, that is located in the folder where file has been situated
  • To shift towards the process of completion, shut down Mozilla Thunderbird by clicking on Cancel
  • For problems related to Inbox and Inbox MSF files erase them permanently. Put the names of files/folders that are causing problems
  • Restart Mozilla Thunderbird Program after completing all steps

Final Outline

The problem mentioned above happens because of limitations present on Windows Platform. Maximum times, the file size is huge in size, even that can get users in problems. The folders or inboxes in Mozilla Thunderbird exceeds by size if it is not compacted or if it comprises of many mails. Henceforth, trying the recommended solution upwards will also be beneficial in solving the Thunderbird Inbox is Full and Can’t hold any more message Error.