How to Solve “Outlook Mailbox Is Full Can’t Send Messages” Error?

Outlook Mailbox is Full: Your mailbox is full, you may not be able to send or receive items.

Have you come across this error and not able to send or receive emails? Although Microsoft has increased PST size in the latest Outlook versions; Still many users encounter this error message saying, "Your Mailbox is full, you can't send messages". No worries! After going through this article, you will be able to reduce the size of the Outlook mailbox and send and receive new emails again like before.

Outlook mailbox is full

Why is my Outlook saying my mailbox is full?

Outlook saying Mailbox is Full error message generally occurs when the PST file reached its maximum storage limit. To fix the error, you will have to minimize the mailbox size in your Outlook. In this article, we're going to provide you four different ways to reduce the Outlook mailbox size to resolve Outlook mailbox full error.

Consequences of an increased Outlook Mailbox Size: 

  • Low productivity, Outlook might hang occasionally 
  • PST file might get corrupt because of a large mailbox data
  • Outlook data loss
  • Unable to send or receive new emails

How do I fix Outlook mailbox full error?

Outlook mailbox quota exceeds after frequently sending and receiving emails for a certain period of time. It increases the size of Outlook Mailbox and occurs more frequently with users with emails that consist of media files like photos, templates that are of large size. Here are few methods to quickly reduce the size of Outlook Mailbox:

1. Delete Large Emails and Attachments to get rid of Mailbox Full error

  • Open Outlook and click on the Home tab scroll down to select on Search Folder
  • Click on New Search Folder
  • Scroll down and under Organizing Mail click on Large Mail


delete large emails to solve Outlook mailbox is full

  • Then click on Choose under Customize Search Folder 
  • Specify the size in the ‘Show mail greater than’ box and click OK to continue.
  • Click on OK again. A new folder named ‘Larger Than xyz KB’ will be created under Search Folders. Now the folder will get updated with the mails of the size that you have specified automatically.
  • Then open this folder and delete all unnecessary emails. 

2. Cleanup Tools Feature to Reduce Outlook Mailbox Size

  • Open Outlook and go to the Files tab and click on Info
  • Under the Info, tab click on Tools > Mailbox Cleanup

Mail cleanup to fix Outlook mailbox is full

  • From here you can select the items older than 3 to 4 months and whose size is more than 1 or 2 MB
  • Click on the Find button, delete all the items which are no longer needed

Find option

  • Then delete the space occupied by Empty Deleted Items. For that;
  • Again open the Mailbox Cleanup toolbox
  • You will see a button to View Deleted Items Size

delete empty spaces to fix Outlook mailbox is full

  • Click on Empty to permanently delete these items and create space for new messages

3. Archive Older Items using AutoArchive

Periodically archiving your Outlook folders will keep the mailbox size small. You can create the archive.pst file that can be updated at a specified location according to your requirement, usually your local hard drive. This is useful because the archived items will be removed from your Outlook mailbox hence reducing the size and moved to the archive file based on the settings you determine. 

Microsoft Outlook includes an AutoArchive feature to archive the old or unrequired PST file items. Following are the steps to perform this.

  • Open Microsoft Outlook application.
  • Navigate to Files>Options>Advanced

Click on advanced


  • Navigate to the AutoArchive section and click on the box saying AutoArchive Settings under it.
  • Now select the checkbox saying Run AutoArchive every day and provide the number of days as an interval for the regular automatic archiving process.

Autoarchive mails to resuce mailbox size

  • Click on OK

Outlook gives you the option of compressing the data files manually. This helps in restoring some extra space in the mailbox. Before starting the procedure, delete the items that are not required. Go to the File tab and click on Tools. Click on the Deleted Items folder and then click on yes and permanently delete the Deleted items folder. Then follow the steps given below:

  • In the File tab, select Account Settings and then click on Account Settings
  • Then click on the Data Files tab, select the PST file to compact, and then click Settings

Outlook mailbox full resolution

  • Then click on Compact Now 

compact PST to fix Outlook mailbox is full

Hopefully, the above-mentioned solutions will help you in keeping the Outlook Mailbox compact and will not reach its maximum storage quota.

However, if the error keeps popping up even after deleting unnecessary data, it can be because of mailbox corruption. PST file size is one of the main culprits behind Outlook mailbox damage. This happens because working with an oversized PST file often leads to crashes and corruption of the database. 

But there are more reasons as well that can cause PST file corruption. The most common ones are sudden shutdown, power failure, abrupt closing of Outlook application, software issues, hard drive failure, or virus infection.

Thus to rectify the Outlook mailbox full error if the mailbox is corrupt, you will have to repair the Outlook data file. Repairing the data file will stop the error and you will be able to resume communication via your MS Outlook account. 

Outlook provides an inbuilt inbox repair tool. Using this you can diagnose and fix the damaged Mailbox. However, if the extent of corruption is more, it is recommended to use a professional PST repair tool like Remo PST Repair. As if the corruption is not repaired with a reliable tool there are chances of important Outlook data loss. 

4. Use a PST Repair Tool to Fix Corrupt Outlook Mailbox

Download the Remo PST Tool for free and recover and repair corrupt Outlook Mailbox. 

Download button

  • Launch the Remo PST Repair tool, and select from the three options

Remo PST Repair to fix Outlook mailbox is full

  • Next, you can choose between two scan options Smart Scan and Normal Scan

Remo PST Repair Scan process to fix Outlook mailbox is full

  • Click on Repair to start the PST repair process. After completion of the repairing process, you can Preview the repaired PST file in the Outlook styled browser.

Remo PST Repair save option to fix Outlook mailbox is full

  • Once the repairing process is successfully done, activate the tool and save the repaired PST file.

After fixing the corruption, you can go ahead and reduce the size of the mailbox using the above-mentioned methods. This will avoid your mailbox from getting corrupted in the future because of the oversized mailbox data. 

Wrapping Up:

As the size of the mailbox increases, the probability of the mailbox becoming corrupt also increases. The specific size limitations of PST file is one of the major cause of Outlook corruption. Thus, if you encounter the issue of a damaged Outlook mailbox because of the mentioned reasons in the write-up; Keep this automated tool Remo Repair PST as a backup plan to repair the Outlook and recover data safely.

How to Solve “Outlook Mailbox Is Full Can’t Send Messages” Error? was last modified: October 26th, 2021 by Tony Landry

Leave a Reply

Your email address will not be published. Required fields are marked *