What To Do When Outlook Mailbox Is Full? Solved

Rollins Duke   
Published: May 1st, 2024 • 6 Min Read

Are you tired of receiving constant notifications about Outlook storage full and thinking “What to do when Outlook mailbox is full?” If you’re unable to send or receive emails due to error messages like “your Outlook mailbox is full” or “mailbox size limit exceeds,” don’t worry!

In this article, we will guide you through various methods to resolve this issue. This is the most common issue when Outlook says mailbox is full or exceeds its size limit, resulting in the inability to receive new emails.

Why Is Outlook Saying My Storage Is Full?

There are several reasons why Outlook says mailbox is full. Here is a common explanation for receiving Microsoft email full storage notification:

  • Exceeding the Maximum Size Limit: Outlook imposes a maximum size limit of 2 GB to 50 GB as per Outlook edition for users. Once this limit is surpassed, you won’t be able to send or receive emails, and Outlook start saying mailbox is full. Even a large PST file crashes Outlook when users try to start it.
  • Cache and Junk Files: Besides important data, your Outlook mailbox may contain cached or junk files. These files can make some of your data unreadable or invisible, then Outlook says storage is full.
  • Third-Party Plug-ins: While third-party tools can be beneficial if they are secure, some may have logical issues that can affect Outlook’s storage. Choosing reliable third-party add-ins is crucial.
  • Attachment Size: If you frequently send and receive emails with large-size attachments, then it consumes significant storage space, and you see Microsoft Outlook full storage notification.
  • Sync Issues: Sometimes due to improper synchronization settings, Outlook might start downloading duplicate emails. So, make sure you are using the correct sync setting then follow the guidance to remove duplicate emails in Outlook PST file.

What Happens When Outlook Mailbox Is Full? Know Its Consequences

Do you know what happens when the Outlook mailbox is full, several issues may arise, affecting your productivity and data:

  • Decreased Performance and Possible Hangs: The overall performance of Outlook may decline, and the application could hang or freeze at times.
  • Increased Risk of Data Corruption: If the mailbox exceeds its size limit, there is a higher chance of your important PST file or data getting corrupted.
  • Potential Data Loss: Outlook email storage full error can lead to data loss, making it vital to address this issue promptly. Then users search solution to resolve the “What to do when the Outlook mailbox is full” query.
  • Inability to Send or Receive Emails: When your Outlook storage is full, you won’t be able to send or receive email messages.
  • Error Notifications: Microsoft email full storage notification starts alerting you that your mailbox is over its limit.

If you’re facing these problems, continue reading for effective solutions.

What To Do When Outlook Says Mailbox Is Full – Know Methods

Outlook offers a few manual methods to tackle Outlook storage full errors, although they can be time-consuming and not specifically designed for fixing mailbox size issues. Here are a couple of approaches:

#1 Fix Outlook Storage Full Error Deleting Large Items

  1. Open MS Outlook on your computer.
  2. For the next step, you need to go to the “Search Folders“.
    Search folders
  3. Then you have to click on “New Search Folder“.
    New search folders
  4. Scroll down and select the “Large Mail” option from organizing mail.
    Large mail
  5. Click on “Choose” and specify the size larger than the desired limit (XYZ KB) to delete.
    Choose button
  6. Enter Mail Size to show mail greater than the specified size and press “OK“.
    Show mail larger than
  7. Finally, open those folders and delete unnecessary large items.
    Fix Outlook Storage Full Error

#2 Free Up Space on Outlook Using Compact Option

  1. The initial step is to go to “Account Settings” in the “File” tab.
    Account settings
  2. Now see configured email accounts and navigate to the “Data Files” tab.
    Data files
  3. Select the Outlook Data File you wish to compress and click on “Settings“.
    Choose settings
  4. Now choose the “Compact now” option to resolve the Outlook storage full error.
    Compact now
  5. The compacting process is initiated, please wait until completion.
    Free Up Space on Outlook

Note: Even after deleting unnecessary data or compressing large PST files, the error may persist due to mailbox corruption. Oversized PST files often lead to crashes and database corruption. If the above-mentioned techniques fail to resolve your query, then go with the upcoming solution.

#3 Empty Folder Option to Clear Outlook Storage

  1. Launch MS Outlook on your computer.
  2. Choose the Delete Items/ Junk Email folder accordingly.
  3. Right-click on the selected folder and choose “Empty Folder“.
  4. Everything in the selective folder will be permanently deleted, click “Yes” to continue.
    Clear Outlook Storage

What To Do When Outlook Mailbox Is Full – Use Software

Manual methods such as deleting large PST files or compressing them may not be sufficient to resolve the Outlook mailbox exceed error. In such cases, PST Splitter Software comes to the rescue. This tool offers a user-friendly solution with just a few clicks. It effectively reduces PST file size in all Windows editions, providing a complete resolution. It supports both ANSI and UNICODE files and effortlessly splits Outlook PST files by year, automatically reducing their size.

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How to Fix the Outlook Mailbox Is Full Error?

  1. Download and install the software on your computer.
  2. The software will automatically detect your Outlook profile or allow you to select files manually.
    Add Outlook profile data
  3. Choose a recovery mode if any corrupted files are detected.
    Use recovery mode
  4. Select the required folders from the software window and press “Next“.
    Required folders
  5. Browse the destination path to store resultant files.
    destination location
  6. Navigate to the split options and select “Split by size“.
    What to do when Outlook mailbox is full
  7. Click on “Split” to start this process.
    Outlook says storage is full


Running out of mailbox space in Outlook can be frustrating, hindering your ability to communicate effectively. Following the methods outlined in this article, you can successfully resolve the issue as we have discussed what to do when the Outlook mailbox is full. Remember, manually deleting unnecessary data and compressing PST files may not always be sufficient. In such cases, reliable third-party applications offer a comprehensive solution. With its user-friendly interface and efficient splitting capabilities, you can easily increase Outlook mailbox size. Don’t let an over mailbox limit your productivity and communication—take action today and keep your Outlook experience seamless and hassle-free.

Frequently Asked Questions

Q 1: What do I do when my Outlook mailbox is full?

Above we have explained 3 manual methods and 1 professional method to fix “Outlook Storage Full” errors.

Q 2: What happens when Outlook mailbox is full?

If you exceed the maximum PST file size limit, your Outlook is slow to receive emails and may become a reason for corruption in data.

Q 3: Why does my Outlook keep saying my storage is full?

All Outlook versions have specific maximum file size limitations that depend on the Outlook edition. If you exceed the maximum file size limit, then Outlook shows a mailbox limit exceed error.