How to Resolve ‘Outlook Data File Reached The Maximum Size’

Summary: Oversized or large OST files can lead to performance issues in Microsoft Outlook and sometimes can cause data corruption. This can happen due to several reasons. In this article, you will learn the reasons and various solutions to troubleshoot and resolve the outlook data file reached the maximum size, including the use of an OST to PST converter tool to restore emails if the error can’t be resolved.

Microsoft Outlook stores all mail items, including your emails, contacts, attachments, notes, etc. in an Outlook data file known as Outlook Storage Table (OST). It creates a file with the .ost extension and stores it at the default location. As you send and receive new emails, the OST size starts growing. If you send or receive multiple emails often with large attachments or images, it can quickly inflate the OST file size. In such cases, you are most likely to encounter the OST file maximum size issue in Microsoft Outlook 2007, 2010, 2013, 2016, 2019, and 2021.

Also Read: Introduction to OST File, its Problems and Solutions

In this article, you will learn the reasons for the ‘OST files reached maximum size’ issue, its causes, indicators, and different solutions you apply to address the OST file maximum size issue and restore your Outlook emails.

Causes of the Outlook Data File Reached Maximum Size

The OST file format is used by Microsoft Outlook to store a local copy of the user’s mailbox on the computer. The maximum size limit of the OST file varies based on the Outlook version. For instance, the OST file size limit was 2 GB in earlier versions while it’s 50GB in the latest versions, including Outlook 2016 and later.

The OST file doesn’t necessarily have to reach the 50GB limit to cause the issue. It may happen as the OST file crosses the 20-25GB recommended limit. In many instances, the issue was observed when OST crossed the 10GB size. This is due to the fact that Outlook requires faster RAM, storage, and processing to process such large OST files. When it can’t process, it leads to the OST file size maximum issue. Similarly, you cannot exceed the 2GB limit in older Outlook versions.

Indicators of Large or Oversized OST File

• Slow performance
• Freezing
• Data corruption 
• Face issues while sending or receiving emails
• Outlook may crash frequently

Therefore, it is essential to resolve the OST file maximum size issue to ensure that your system runs smoothly.

Also Read: Unlock the Secret: Free Methods to Convert OST to PST in Outlook

Solutions to Fix the Outlook Data File Reached The Maximum Size

This issue can leave you feeling frustrated and powerless. However, it’s a common issue for users attempting to manage large amounts of data in their Outlook accounts.

Fortunately, there are some easy solutions that you can apply to resolve this problem and get your important emails back where they should be.

Method 1: Archiving Old Data

One of the most effective ways to resolve the OST file maximum size issue is to archive old data. Archiving involves moving old emails, calendar items, and other data to a separate file. This helps to reduce the size of the OST file and improve Outlook’s performance. Users can also set up automatic archiving to ensure that old data is regularly moved to a separate file.

In your Microsoft Outlook, follow these steps:

Do one of the following:

• In Outlook, go to File > Info > Tools > Clean up old items.
• Select Archive this folder and all subfolders option.
• Select the mail folder and then choose or enter a date from the Archive items older than the field.
• Select Include items with the “Do not AutoArchive” 
• Click OK.
• Repeat and continue the steps to split the OST file based on different date ranges.
• You may also enable Auto Archive option.

Method 2: Compact Now

Compacting or compressing the OST file is another effective method to resolve the OST file maximum size issue in Microsoft Outlook. This allows you to reduce the oversized or large size OST file and thereby, resolve the OST file reached maximum size issue.

The steps are as follows,

• Open Outlook
• Click File
• Go to Account Settings and Account Settings again
• Click on Data Files and select the OST data file

• Then click Settings > Advanced > Outlook Data File Setting
• Select Compact Now and then click OK.

• This compacts the large OST file and reduces the OST file size.

Method 3: Splitting the OST File- Outlook Data File Reached Maximum Size

you may also split the OST file into smaller PST files to resolve the maximum size issue. This involves exporting mail folders and items to multiple smaller PST files OST via Outlook import/export wizard.

The steps are as follows:

• Open Microsoft Outlook and then click File > Open & Export. From the drop-down, select Import/Export.
• Click on Export to a file and click Next.
• Choose Outlook Data File (.pst) and click Next.
• Select the mail folder and click Next.
• Select a location and make sure you enter a proper name.
• Click Finish to begin the export process.

Repeat these steps to split OST mail items into multiple PST files and then remove them from the OST file to reduce the file size and resolve the OST file reached maximum file size.

Method 4. Rebuild Outlook Data Files

Sometimes the error is caused when the OST is inconsistent or inaccessible due to oversizing. If you can’t resolve the issue with the help of the aforementioned methods, you can try to recreate the OST file by following these steps::

• Close Outlook
• Launch “Control Panel“, find and click on “Mail.” This opens the “Mail (Microsoft Outlook)” dialog box.
• Click on “Data Files“

• Choose the Outlook (.OST) data file linked with your email account and click “Open File Location“
• Rename the OST file by editing the file name with the .bak suffix. This will create a backup copy of the OST file.
• Start Outlook. It will automatically create a new OST file and synchronize all mail items from the mailbox server and resolve the OST file reached maximum size issue.

Method 5: Using OST to PST Converter Tool to Resolve the OST File Maximum Size Issue

Sometimes. OST file rebuild may fail when the user profile is deleted or disabled from the mailbox server. In such cases, use an OST to PST converter software, such as Stellar Converter for OST. The software helps you extract all mailboxes from inaccessible, oversized, and orphaned OST files and save them to an Outlook importable PST file. You can also use the software to directly export mail items from OST files to an existing Outlook profile, Live Exchange Server, or Microsoft 365 mailbox.

The tool is also designed to compress your large or oversized OST file or split it into smaller PST files. You can choose these options while converting your OST file to PST format.

After the conversion, you can import the converted PST file to your new Outlook profile or account on any PC or Mac via the Outlook Import Export wizard.

Conclusion

The OST file maximum size issue prevents users from accessing their emails or opening Outlook. This happens when the Outlook data file (OST) becomes too large or exceeds the maximum recommended file size (~10-20GB). A large or oversized OST can also lead to data corruption and slow Outlook performance. Thus, it’s critical to resolve the issue asap to prevent any data loss situation. By following the different methods discussed in this article, users can resolve the OST file reached maximum size issue and ensure that their data remains safe and secure with the help of an OST to PST converter tool, such as Stellar Converter for OST.

Also Read: Difference between OST and PST