Learn About Thunderbird Maximum Request Size Exceeded Issue

Mozilla provides a perfect email client for all Mac, Windows, and Linux users in Thunderbird. It can create, send, and receive emails through IMAP and POP3 accounts. But, sometimes people find that they are receiving an error message saying ‘ uid max mailbox size exceeded Thunderbird ’ or  “Thunderbird error message size exceeded”. This indicates a space issue in saving emails to the Thunderbird application.

Users face challenges in reading, sending, and receiving daily emails. This post describes all the steps and ways necessary to solve the error: Thunderbird maximum request size exceeded. Read the following segment to figure out the best way to resolve the error when Thunderbird’s maximum literal size is exceeded.

Know all about Thunderbird’s mailbox size limit and managing storage. All pros and cons are explained in the sections below.

What is Thunderbird Mailbox Size Limit?

As we know, the Thunderbird stores all default folders in a separate MBOX file format. Let’s understand the storage limit for all folders.

• Latest Thunderbird versions do not impose any mailbox size limit. But it also recommends following the 4GB maximum mailbox size limit.
• The older version of Mozilla Thunderbird imposes to 4GB maximum file size limit.
• For an IMAP account, it imposes the same limit as for a POP account.
• It mentioned that Mozilla suggests storing 4 billion available and deleted messages.

What if Thunderbird Mailbox Size Limit Exceeded?

The following are some of the many issues faced by users who have large-sized Thunderbird mailboxes. So let’s understand the outcome of the Thunderbird email storage limit issue.

• Unable to send and receive emails on the email client without errors.
• An error message, ‘ uid max mailbox size exceeded Thunderbird ’ is shown.
• Cannot read email messages from the Inbox folder.
• Unable to delete emails and free space on the server.

Reasons for Thunderbird Maximum Request Size Exceeded

Here are the top few reasons as to what causes error messages to pop up in a TB configured email account:

• The recipient has too many emails, and the server isn’t accepting any more.
• Using an abandoned account that has not been checked or cleaned for years.
• Limited mailbox space that creates an error, ‘ UID max mailbox size exceeded ’.
• Thunderbird mailbox folders cannot exceed the 4GB limit
• An issue with the Windows platform and Thunderbird v3.1.
• There is some corruption in the Thunderbird MBOX files.
• Antivirus or firewall software has deleted or quarantined Thunderbird storage files.

Methods to Check Mailbox Size

The following are some of the different techniques and procedures to resolve the error: Thunderbird Maximum Request Size Exceeded & recover email data from a corrupt Thunderbird profile:

Solution-1: Check Deleted Items Settings

Follow the steps below to check the deleted items and apply the required settings:

• First, Launch the Thunderbird Application.
• Then, go to Tools >> Account Settings >> Server Settings.

• Next, select Leave messages on the server.
• Then, select an appropriate number of days to manage Thunderbird mailbox size limit & resolve Thunderbird Mailbox Size Limit Exceeded.
• Also, select the option to keep messages Until I delete them.
• Finally, click OK to save changes.

Solution-2: Manage Disk Space when Thunderbird Max Message Size Exceeded

The local drive gets full, and the Thunderbird mailbox size is not too big. Then it will create an issue, managing space on the same drive. It’s an indirect way to fix Thunderbird’s maximum mailbox size issue:

• First, go to Thunderbird>>Tools>>Account Settings>>Disc Space.

• And select don’t delete any messages option.
• Also, select Always keep starred messages to check the mailbox size in Thunderbird when Thunderbird’s max message size is exceeded.
• Finally, click OK to save changes.

Solution-3: Compact Folders in Thunderbird

Compacting the Thunderbird folder can also make some space in the mailbox for new emails. Follow the belw steps:

• In earlier versions of Thunderbird 3.1, change the Folder view to All.

• Then, right-click and Inbox folder and select Compact to solve the error Thunderbird Maximum Request Size Exceeded to an extent.

Solution-4: Recreate the Deleted Items Folder

It is also a way to act in case Thunderbird surpasses the maximum mailbox size limit.

• First, open the Thunderbird profile to delete emails in Thunderbird.
• Then, click the three bars on the top-right corner and select Help >> Troubleshooting Information.

• From the Application Basics tab, click on the Open Folder button.

• Next, Exit Thunderbird.
• From the file explorer window, go to the Mail folder and select the email account having the Thunderbird mailbox size limit exceeded issue.

• Now, select the Trash and Trash.msf file and delete them.

• Then, restart Thunderbird and create a new folder with the name Trash.

Solution-5: Upgrade Thunderbird v3.1

Sometimes using an older version can also create a malfunction. So, upgrading it to a new version also become quite handy to deal with the Thunderbird mailbox size limit exceed issue.

• Go to the Menu bar >> Help >> About Thunderbird.

• This will remove any Thunderbird large folder issues or Thunderbird error message size exceeded error.

Note: Another Alternative is to try splitting the large-sized MBOX file to avoid

• Then, configure the same email account on the new version of Thunderbird.

Solution-6: Contact ISP Support

• If nothing else works, contact the email service providers to increase the mailbox quota of the email account in question.
• Otherwise, ask them to delete some emails from the server

Solution 7: Move to New Profile

• Often, antivirus software deletes some storage MBOX files during quarantine.
• Recover the MBOX email file and place it back in the Mail folder to remove the Thunderbird Maximum Request Size Exceeded issue.

Solution 8: Use an Automated Solution to Manage Thunderbird Mailbox

Often, the manual solution is not able to resolve the issue: Thunderbird’s maximum literal size is exceeded completely. Either email cannot be recovered for a POP3 account, or errors are generated again and again over time. In such a case, one looks to view emails through WebMail or Outlook. This can be easily done by using the SysTools MBOX to PST Converter. It extracts email data from the Inbox.mbox file and transfers it to a format compatible with MS Outlook. It is an easy fix to resolve the error Thunderbird mailbox size limit exceeded.

Conclusion

Thunderbird is a well-known email client, but sometimes errors can persist in best of applications. It is required to regularly check the mailbox size in Thunderbird and keep compacting folders when Thunderbird’s maximum literal limit is exceeded. This post describes all the necessary ways to fix the Thunderbird maximum request size exceeded issue in version 3.1. Another alternative solution is also mentioned to use an automated software to make the task easier and direct.