Reduce Outlook Mailbox size by Manual Method

Updated on September 04, 2023 by Savita Sharma

We all know that Microsoft Outlook is one of the most used email clients, as it offers a lot of advantages to its users. But its excessive use leads to oversized mailbox. Whenever the mailbox size of Outlook crosses the recommended size, users get a notification. A notification from Outlook that says your mailbox is full of messages and you need to reduce your mailbox size for further use. For some reason, there might be a lot of unwanted emails and attachments in your mailbox that you still need to clear out for the time being; that's why your mailbox now has no space.

But before starting the mailbox-reducing process, you must take a backup of the Outlook PST files. You can easily do it by using the Regain Outlook PST Recovery software.

What Issues You May Face Due to Excessive Mailbox Size in Outlook?

Excessive mailbox size in Outlook can lead to several problems, making using email a frustrating experience. Here are some common issues:

Slow Performance: When your mailbox gets too big, Outlook can become sluggish and take a long time to open, send, or receive emails. This is because it has to load and manage a lot of data.

Freezing or Crashing: Large mailboxes can cause Outlook to freeze or crash, especially when performing tasks like searching for emails or opening attachments.

Difficulty Searching: It becomes harder to find specific emails when your mailbox is overflowing. Outlook's search feature may need to be fixed, or it might take a long time to show results.

Sync Problems: If you use Outlook on multiple devices, like a computer and a smartphone, a large mailbox can lead to synchronization problems. Emails may only appear consistently across some of your devices.

Email Send/Receive Failures: Large mailboxes can trigger errors when sending or receiving emails. You might get error messages that prevent you from sending or receiving essential messages.

Storage Issues: Your email server may have a storage limit, and an oversized mailbox can lead to you needing more storage space. This can prevent you from receiving new emails.

Backup and Recovery Problems: Backing up and recovering your emails becomes more challenging with a large mailbox. Creating backups can take a long time, and restoring emails may take much work.

Increased Vulnerability: A big mailbox can be a tempting target for hackers and cyberattacks. Keeping unnecessary emails can expose you to security risks.

To avoid these problems, it's a good practice to regularly clean up your mailbox by deleting unnecessary emails and attachments, archiving old emails, and organizing your messages into folders. This will help keep your Outlook experience smooth and efficient.

How to Reduce Outlook Mailbox Size Easily?

As you have read above, it's common to have the above errors if your mailbox is full. Most of the time, you will receive send-and-receive mistakes, such as being unable to receive emails because there is insufficient space in your Outlook mailbox to add more emails.

Deleting some emails is the first aid to curing this issue. But the reasons for this situation can be different depending on many materials. This post will teach you about multiple methods to deal with this total mailbox error. Keep reading and applying.

Solution 1: Remove the Large Emails with Attachments

There is no other easy way to delete extra-large emails with more significant attachments. But deleting emails manually, one by one, is too disgusting. However, you can perform the deleting process with an in-built facility in Outlook. Read as follows:

  • 1. First, run Outlook and in the folder list, press on the search folder option. Then choose a new search folder.
  • How to Reduce Outlook Mailbox size
  • 2. Next, scroll down your mouse's wheel and under the section of "organizing mail," choose "large mail" and just press "choose.
  • Manual Tips to Reduce Outlook PST file size
  • 3. After that, provide a specific size in the box named "show mail greater than" and just press the OK option to begin the process.
  • Remove large attachments to reduce Outlook Mailbox size
  • 4. Press the OK button again and a folder will be created with your given specific size. Here you will find all the emails and attachments of that size that you have selected previously.

You can delete the folder to get some more space. However, you can also create a specific folder. Whenever you get the error of low area in your Outlook mailbox, you can quickly delete the folder and get the additional fixes.

Solution 2: Archive or delete the old PST files

An in-built facility in MS Outlook can archive your old and unwanted PST files into a different PST file on your device's local Drive. Now, attempt the steps as follows:

  • 1. First, run MS Outlook and navigate to Files > Options and then "advanced".
  • 2. Then go to the "auto archive" section on the menu and press on the "auto archive settings".
  • 3. Next, mark the checkbook "Run AutoArchieve." (you can select the desired number of days).
  • 4. Input other options like deleting old items or others, and lastly, just press "auto archive".

Solution 3: Use the built-in Mailbox Cleanup tool

Usually, there is an in-built feature of Outlook through which you can reduce the size of your Outlook mailbox. Follow the steps and procedures below to access the Outlook mailbox cleanup tool and lessen the size.

  • 1. After opening Outlook, go to the "file" tab. From there, go to the "info" section and select the "Mailbox Cleanup" tool.
  • Free Manual ways to Compact PST file size
  • 2. If you double click on the mailbox cleanup, you will get three options under it as a drop-down list. They are as follows:

    • Mailbox Cleanup
    • Empty
    • Archive
  • 3. The first option, "Mailbox Cleanup," is generally used to see your mailbox size and find the folder with your given specific size.
  • Reduce or compact PST file size manually
  • 4. It also has the facility to archive items. By just pressing on the "AutoArchive", you can easily archive the unwanted items and move them to your desired location.
  • step by step process to compress Outlook mailbox size
  • 5. Using the "Empty" option, you can easily delete (permanently) all the items from the deleted items folder. You have the opportunity to view the folder.

Solution 4: Split or Divide the Large PST Files

In MS Outlook, data files are usually stored in PST files. Some PST files are so large that they occupy a considerable space in the mailbox. Don't worry; you can compress or split them to reduce the mailbox size. You can do it manually or through automated software.

For the manual method, you need to delete the unwanted files first. Go to the navigation panel, right-click the deleted items folder, and press "Empty." After that, follow the steps outlined below.

  • Run Outlook and in the "file" tab, press on the "account settings".
  • Navigate to the "Data Files" tab, then choose the PST files to compress and press on the "settings".
  • Lastly, in the "Data File" dialogue box, just press on the "Compact Now" option.

Besides, you can use automated software. You can easily split or divide the large-sized PST files into small sizes using the Regain PST Splitter software the most extensive facility you will love is its easy and stunning interface.

How to split Outlook PST files using the Regain PST Splitter?

It's so simple to reduce Outlook Mailbox file size using this software. The steps are as follows:

  • 1. Firstly, install the software and run it on your device.
  • 2. Then choose the files that you want to split.
  • Regain PST Splitter tool to split oversize pst file
  • 3. After selecting your desired files, just click on the next button.
  • Add PST files
  • 4. Provide the size limit, and apply other filters if needed.
  • Select PST Size
  • 5. Provide a location (destination path) where you need to save the files.
  • select destination
  • 6. Lastly, files will be saved at your given location after completing the splitting process. You will get a message that the split process has been completed.

Software Features:

  • Offers various PST file splitting options such as Split by Size, Split by Date, Split by Year, Split by Email ID, Split by Contain Words, To, From, Cc, Bcc, and Subject.
  • Supports splitting corrupt, damaged, or inaccessible, password-protected Outlook PST files and Outlook PST Archive files by date, size, year, or folder.
  • Maintains the email integrity, email properties, folder structure, integrity, and hierarchy of Outlook PST files.
  • Splits large or oversized Microsoft Outlook PST files into smaller PST files and creates a Log Report to compare PST files on Split PST file process completion and saves in CSV format.
  • Splits large-sized Outlook PST files without Outlook installation and supports searching Outlook PST files from Drive.
  • Allows splitting Outlook contacts and calendar items apart from email items and makes a new folder to save the newly-created PST files.

Final Words:

This article discusses the various issues that could happen due to increased Outlook mailbox size and the different manual methods for reducing Outlook mailbox size. We recommend using an advanced and professional Regain Outlook PST Splitter tool to split large-sized or oversized Outlook PST files into smaller PST files and thus help prevent PST files from getting corrupted due to oversize. This third-party tool is also available as a free Demo version to let users check its capabilities before purchasing the fully licensed version.


Frequently Asked Questions:

Q1: How can I back up my Outlook PST files before reducing mailbox size?

Ans: To back up your PST files, use the "Regain Outlook PST Recovery" software mentioned in the blog. It helps ensure your data is safe before making changes.

Q2: Is there automated software to split Outlook PST files to reduce mailbox size?

Ans: You can use the "Regain PST Splitter" software mentioned in the blog. It offers various splitting options and is user-friendly.

Q3: What are the key features of the Regain PST Splitter software?

Ans: The Regain PST Splitter software offers various splitting options, supports damaged PST files, maintains email integrity, and creates a log report for tracking. It's a comprehensive tool for managing PST files.

Q4: Is there a free Regain PST Splitter software version to try before purchasing?

Ans: The blog mentions that a free demo version of the Regain PST Splitter is available for users to test its capabilities before purchasing the fully licensed version.

Q5: Why is reducing Outlook mailbox size important for preventing PST file corruption?

Ans: Reducing mailbox size helps prevent PST files from becoming too large, which can lead to corruption. Managing mailbox size is crucial for maintaining the integrity of your email data.