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What is an OST File? Its problem and solution

Summary: This article covers a detailed explanation of the Outlook OST files. Here, we will talk about what is an OST file and the problems associated with it. We will also discuss about the solution to fix the issues from the OST files.

Outlook uses the official storage table, commonly known as OST files, to save synchronized or downloaded data such as contacts, calendars, emails, journals, etc. It is just possible even with an internet connection, which makes OST files important. However, along with the advantages of the OST files, there are various problems associated with them.

Detailed Overview of the Offline Storage Table (OST)

When you choose Exchange,, Office 365, and IMAP to create your profile in Outlook, then OST files are automatically created. An OST file saves a copy of the mailbox data like emails, contacts, etc. The OST files allow accessing the data even when the internet connection is not available.

In the offline mode, the user can create an entry in the calendar and compose an email, but you can’t be able to send or receive it. After the connection gets restored, then changes/alterations made during the offline mode are performed.

Outlook also creates PST files, which also save data like journals, emails, contacts, etc. The working of this file is just similar to the OST file, but the main difference between them is that the PST file is movable from one system to another, which is lacking in the OST file.

Apart from the one problem, there are various factors that cause issues in the OST file. Corruption in the file is one of the probable problems that cause users to look to convert an OST to a PST file.

Before looking down into the insights of the OST file, it is a must to know the location where the OST file is stored in the system.

Location of the OST file

For Outlook 2000, 2003, 2007 versions

C:\Documents and Settings\User Name\Local Settings\Application Data\Microsoft\Outlook

For Outlook 2013, 2016, and 2019 versions


If you are unable to find the location of the OST file, then follow the listed steps shared below:-

  • After opening the Outlook, you need to click on the file.
  • A new window will appear where you need to find out Account Settings and then click on Account Settings.
  • After that, go and search for the data file tab. Click on the OST file, and after that, click on the open folder location.
  • In the end, a dialog box displaying the by-default OST file location will appear.

Why does the OST file get corrupted?

After knowing the brief about what is an OST file, we will now be moving forward toward knowing some of the reasons that make them corrupted. One of the fundamental questions is, why do the OST files get corrupted? To make it simple, we have prepared a list of some reasons:-

  • One of the common issues that corrupted the PST was the abrupt closure of Outlook.
  • If the size of the OST file increases over its permissible size limit,
  • App installed on the system can bring viruses, which may increase the chances of corruption in OST files.
  • An OST file is stored in the same location where the hard drive has the bad sectors.

Solutions to Resolve the Issues of the OST Files

Many solutions help to fix the issues from the OST file, and one of the best solutions is to convert an OST to PST file. Apart from that, the user can also look to recreate the OST file, which is also the best solution to deal with the issue.

Solution#1: Re-creation of the OST file

Re-creation of the OST file is also the solution to deal with the solution in a better manner. The step to perform this method has been given below:-

  • After opening the Control Panel on your system, look for the Mail option.
  • Click on the Show profile option.
  • Now, in the mail-setup option, click on the Show profile button.
  • Then, click on the Add button.
  • In the new profile, kindly mention the name of the new file and, subsequently, click on Next.
  • In the Add Account window, kindly click on the next button.
  • After that, in the Outlook data file setting, check and select the location to save the file.

These are some steps you can take to recreate the OST file. Now, the next step in our list to convert the OST to PST file.

Solution#2 Fix Corruption from OST files using ScanPST.exe

Sometimes, the OST file catches corruption, which creates issues while accessing the data. Many times, users may encounter an error while opening Outlook.

So, there are solutions like the Microsoft inbox repair utility, which is ScanPST.exe. The working of this utility has been below:-

Please note that this utility only able to sort the corruption issue only when there is a small OST file.

  • Search the ScanPST.exe in your system and then launch it.
  • After that, click on the scan to check the type of corruption.
  • If there is a minor level of corruption, then move ahead with repairing the OST file.
  • Click on the browse button to load the file into the utility.
  • Hit on the repair button to start the utility for repairing the OST file.

After learning about what is an OST file and the manual solution to fix the issues from the OST file, we are now introducing professional third-party software.

Solution#3 Third-party Software to Fix the OST Files Problems

All-in-one solution to repair the OST convert an OST to PST file, there is one solution which is Weeom OST to PST converter tool. This solution helps to repair the files by converting them into a PST file format. It extracts the complete data from the OST file.

It is efficient in converting multiple OST files at one instance into PST files.

Steps to convert an OST to PST using the software

  • After installing the software, open it by double clicking on the software shortcut.
  • Once opened, kindly click on the Add OST file.
  • After adding the OST file, click on OST to PST file from the tool ribbon bar.
  • A window to select/de-select the sub-folders will open.
  • Next, the option to export the data into new and already existing PST will appear. After choosing the desired option, click on Next.
  • The following window will allow the filtering of the data on the basis of the given criteria. Apply them to your needs.
  • The last setting that the software gives you is to map the folders. Choose the folder to map and click on next to start the conversion.
Wrapping Up

To optimize the workflow, it is important to know what is an OST file and its problems. There are several issues that can hit the OST file, which creates problems many times. To solve the issues we have listed some methods which also include the solution to convert an OST to PST file.

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