Microsoft Outlook users two types of Outlook data file: PST and OST. Just like a PST file, an OST file has a certain size limit. This means it can’t store more mailbox content than the size limit. And when it reaches the maximum size or crosses it, Outlook users are likely to confront severe issues. In this article, you’ll learn how to handle an oversized OST file in order to avoid unwanted situations which may lead to corruption and reduce outlook ost file size.

For an Outlook user, Outlook data file is very crucial, be it PST or OST. They both contain the valuable mailbox content of an Outlook user. And this is why they both hold the equal importance. PST is a personal storage table while OST is an offline storage table. Although both the files are associated with Microsoft Outlook client, they’re somewhere different from each other. An Outlook user ain’t familiar with an OST file until unless he/she configures Microsoft Outlook with Exchange Server. If the Outlook client is being used as a stand-alone application, it creates PST file on a local system to store the entire mailbox content. On the other hand, an OST file is created if you configure Microsoft Outlook with Exchange Server.

OST aka Offline Storage Table

An OST file stores the copies of your mailbox content on the Exchange Server. You can work offline with an OST file when the Exchange Server connection ain’t available. And when the Exchange Server connection is reestablished, you can synchronize the changes made earlier. Although OST and PST files have different file structure and functionalities, they both share a few similarities as well. Both OST and PST files have a definite size limit:

Microsoft Outlook Version	File Size Limit
Outlook 2002 and earlier versions	2 GB
Outlook 2007	20 GB
Outlook 2010 and later versions	50 GB

As per the size limitation, the OST file should never cross its maximum size. Because if it does, it may lead to serious troubles. Outlook users often experience performance issues due to an oversized OST file. And if you don’t fix it in a timely manner, you’re likely to face file corruption.

How Do You Get an Oversized OST File?

You might be wondering how you get an oversized OST file. Well, the reason is pretty simple and logical. An OST file stores email messages along with their attachments, contacts, notes, calendars, public folders, and much more. It’s quite obvious that you send and receive a number of email messages every day. Sometimes it may happen that the email messages you receive may contain heavy attachments. Sending and receiving a large number of email messages every day will definitely grow OST file size. And one day, it reaches its maximum size and starts creating troubles for Outlook users.

Generally, most of the Outlook users delete the unwanted email messages and other mailbox content to handle an oversized OST file. But this ain’t helpful. Because whatever you delete from the OST file, it goes to the Deleted Items folder. This means the mailbox content you delete is still present in the OST file.

3 Things You Must Do to Reduce Outlook OST File Size

Whenever you notice that the OST file is near its maximum size, you must take the following corrective measures:

• First, delete all the unwanted mailbox content from the OST file permanently. If you have some important attachments, you can save them separately on your computer system. But don’t keep them in your OST file.
• Also, don’t forget to empty the Deleted Items folder.
• And keep using the Outlook’s Compact feature regularly to compress OST file size.

The aforementioned measures are only helpful if the OST file is near its maximum size limit. But if the OST file has already crossed the size limitation, you must do something to protect your OST file from being corrupt.

How to Handle Oversized OST File?

An oversized Outlook data file is always prone to corruption. If you have an oversized OST file, it’s likely to be corrupt at any time. You can try a few things to reduce Outlook OST file size and avoid corruption or other severe issues even if you have an oversized OST file. I’m sharing some useful tricks below which you can use here:

• Renaming OST File
• Running Outlook in Safe Mode
• Recreating Outlook Profile
• Disabling Outlook Add-ons
• Disabling Antivirus
• Archiving OST File Content

Note: But don’t forget to take backup of your OST file before using any of the manual tricks.

Unfortunately, if you’re late and corruption has already occurred in your OST file, you should try to repair it.

Use OST Recovery Software

OST Recovery software is a smart solution to repair OST file which is corrupt due to any reason. It can scan the corrupt OST file and present a preview of the mailbox content. There are three recovery modes in this software to handle the different level of corruption: Standard, Advanced, and Deep. Via this software, you can successfully restore email messages, contacts, calendars, tasks, notes as well as attachments from corrupt OST file. You can save all the recovered data into a new file of any of these formats: PST, EML, DBX, MSG, and MBOX. Download the demo version of OST Recovery software for free evaluation.