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How to Reduce OST File Size Without Outlook? Solved

Published By Karen Chard 
Rollins Duke
Approved By Rollins Duke
Published On January 31st, 2024
Reading Time 6 Min Read

If your OST file size has increased and you want to reduce OST file size without losing any information, then you are on the right page. here we are going to mention both manual methods and professional tools to accomplish your task. First, read all the methods and drawbacks and then choose the right way, which suits your needs best.

An OST file is created by Microsoft Outlook to store data. It keeps a copy of emails, contacts, tasks, and more from an Office 365, Exchange, or Outlook.com account on the user’s computer. Users can access and work with these files even when they’re offline, allowing them to read and write emails, schedule appointments, and manage contacts.

However, changes to OST files can only be made when the computer is connected to the internet. These offline files take up storage space and can lead to errors and performance issues in Outlook. To address this, users need to reduce OST file size to better manage their Outlook accounts.

Consequences of Large OST Files

OST file bigger than mailbox size can often cause Outlook to slow down, lead to file corruption, disrupt search engine indexing, and trigger various other issues. Some common errors associated with large OST files include:

  • Messages stuck while requesting data from the Microsoft Exchange server.
  • Delays in retrieving data from the Exchange server.
  • Outlook email client becoming unresponsive.
  • Inability to add additional data to an existing Exchange .ost file.
  • Delayed opening of the OST file document.

How to Reduce OST File Size Manually?

Here we are going to use three manual methods to resolve your issues with preserved details. all the methods are given below one by one:

Important Note: Firstly, remove unwanted and old emails from the Outlook mailbox, and then follow these methods. Because after these processes you can’t recover your data.

Method 1: Decrease OST File Size by Compacting

  1. Firstly, go to the File tab in Outlook.
  2. Choose Account Settings >> Account Settings….

    Account Settings

  3. Click on the Data Files tab and choose the needed OST file.

    Data Files

  4. Hit on the Compact Now button to reduce OST file size.
  5. Lastly, click on the OK button.

Method 2: Clean Up Your Mailbox Data

  1. Firstly, open your MS Outlook account.
  2. Click on the File >> Info tab.
  3. Choose the Mailbox Cleanup option.

    Cleanup Tools

  4. Click on the View mailbox size to analyze the mailbox size.
  5. After analyzing your data, click on the Close button.

Method 3: Reduce OST File Size by Archiving

Archiving your emails means moving your old or unwanted emails safely into PST format. all the steps are given below in detail:

  1. Firstly, start your Outlook.
  2. Select the File >> Tools >> Clean Up Old Emails.

    Clean up Tools

  3. Check the Archive this folder and all subfolders option.

    Archive this folder

  4. Choose the needed folders to reduce OST file size.
  5. Lastly, select the destination to save the file and hit the OK button.

Drawbacks of Manual Methods

  • Outlook must be installed and configured with the subscribed account.
  • These methods will not work with corrupted, damaged, or inaccessible OST files.
  • High risk of data loss, while moving data.
  • Technical knowledge and expertise required.

Professional Tool to Reduce OST File Size Safely

Download RecoveryTools OST File Converter to reduce OST file size with preserved information. This tool allows users to shrink OST file by splitting them into 2 GB, 5 GB, 10 GB, and 20 GB. Also, it comes with amazing and advanced features, which makes it more powerful and the first choice of users.

There is no need to download and install any third-party tool or Outlook email client because it’s a completely standalone and independent tool to reduce OST file size. You can download the free demo version to extract only 25 items from each folder so that you can easily analyze it.

Quick Steps to Decrease OST File Size

  • Step 1: After installation, load the OST file data.
  • Step 2: Select the needed folders or subfolders.
  • Step 3: Choose PST as saving type from the list.
  • Step 4: Enable the Split PST option.
  • Step 5: Browse the location as per choice.
  • Step 6: Hit the Convert to reduce OST file size.

All Working Steps to Shrink OST File Size Safely

  1. Firstly, download and install the given tool, and click on the Next button after reading all the instructions.

    tool to reduce OST file size

  2. After that, upload the OST files data automatically (from the connected Outlook profile) or manually using the Select Files and Select Folders options.

    upload the OST files data

  3. Next, select the needed folders or subfolders from the software panel, and after checking it hit the Next button.

    needed folders or subfolders

  4. Choose PST format as saving type from the Select Saving Option list.

    saving type

  5. Enable the Split PST File option to split the resultant data file as per choice, and also you can check the Separate PST per user and Change Language option.

    split the resultant data file

  6. Select the needed location to save your resultant data file using the Browse button.

    save your resultant data

  7. Lastly, click on the Convert button to reduce OST file size.

    reduce OST file size

  8. At last, a confirmation message will show, and click on the OK button.

    confirmation message

Why Professional Tools Over Manual Methods?

  • Two Options: This software provides dual options to load OST files and folders at once to the software panel using the Select Files and Select Folders options.
  • Automatically Load Data: Also, if your Outlook profile is connected to the same machine, whether it’s working or not, it can load complete profile data automatically.
  • Split PST File: if you have chosen PST as a saving option, users can use this option to split their resultant data file into 2 GB, 5 GB, 10 GB, and 20 GB.
  • Use Recovery Mode: This option allows users to repair and support all types of OST files including inaccessible, orphan, damaged corrupted, etc to reduce OST file size.
  • Change Language Option: This option allows users to map their data and folders into different languages including English, Dutch, German, French, Norwegian, Spanish, etc.
  • Exported File Supported in Every Edition: Resultant data file in all Outlook versions including 2021, 2019, 2016, 2013, 2010, and all old versions, also it supports all OST files.

Final Thoughts

Above we have discussed the manual methods and expert solutions to reduce OST file size safely. Both methods are great, but manual methods have some drawbacks. So, it is good to use an expert tool to shrink OST file size while preserving all data. The mentioned tool comes with amazing and advanced features and filters. also, you don’t need to purchase the subscription first, you can try the free demo first to analyze the performance. Hope you find the article helpful.