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Is It Safe to Delete OST File? – A Comprehensive Guide

Published By Ashwani Tiwari
Tej Pratap Shukla
Approved By Tej Pratap Shukla
Published On December 31st, 2021
Reading Time 5 Minutes Reading

There are cases where users ask the question: Is it safe to delete OST file? Although, they do not always get the right answers for it. OST files are Offline Storage Files that store Outlook data in a user’s local computer as database.

But why are users asking such a question? Well, all the OST files contain precious and sensitive information about a user’s business which they need to keep safe. Due to this, the OST files are never moved, deleted, or taken a backup of, creating an issue of the OST file size being too large.


There is another question that arises covering what happens if OST file is deleted? That will also be answered in this article along with the question if deleting OST is safe or not. This write-up will cover what an OST file is (in brief since a lot of users already know about it), how can one delete the files, what are the reasons for deleting these files, and what will happen after deleting them.

Let’s now learn a little about the OST files.

A Brief Overview on Offline Storage Table (OST) File

An OST file is created when a user configures his/her account to Outlook. This file is a replica of the data stored in Outlook account including emails, calendars etc. Also, this will help you to access your data that you have stored in your account even without internet connection. The data being stored into the OST file makes it kind of a database and users who know that are worried and want to know is it safe to delete OST file?

There are various account types that use OST file such as Exchange accounts, Office 365, and Now, all the information that you have modified in the absence of internet connection are stored in OST file. Once you connect your account to internet, all the changes that were made are synchronized to the mail server.

If your account does not have an internet connectivity, you will not be able to send new emails or receive any. But you can compose emails that will be saved in OST file.

Enough about OST files, let’s now check out how is it possible to delete OST files safely and later, what happens if OST file is deleted?

How to Delete OST Files Safely?

The method for deleting your .ost files isn’t too complicated but before that, you should make sure that you take a backup of these files. Why?

Well, these files contain important data and once gone, they are not coming back. In case you need to access these files or even any one of them in future, you should be able to convert them into the other Outlook accessible file format i.e. PST and access them in Outlook.

For that, use the OST to PST Converter Tool and save a backup of your Outlook data in your local computer. This way you can view your converted files in Outlook whenever the need be.

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This practically is the answer to the question: Is it safe to delete OST file? You can delete your OST files if you take a backup of them. Now, look at the steps to delete the files.

1. If your Outlook program is running, close it.
2. Go to the Start button and enter Run in the search bar. In the Run window, type in the given command.


3. Click on OK to get the location of the offline data file.
4. Choose the file you want to delete and hit the Delete option.
5. You will prompted with the following warning to which you have to answer Yes.


Let’s also understand why there is a need to delete the OST files.

Why Does One Need to Delete OST File?

Following are the reasons why users might require deleting OST file but are having doubts and asking queries like is it safe to delete OST file.

1. The one reason for the deletion could be the synchronization errors. Due to these errors, Outlook starts behaving strange and provides abnormal results. You can troubleshoot the account by deleting the copied OST files.

2. Another reason could be because of overloaded space. This will cause the system to freeze and is happened mainly due to the exceeded limit of the file size of OST. When there are large OST files and the space fills up, Outlook stops working.

3. If you have your Exchange account configured with your Outlook account, the data from Exchange will be saved as OST files in Outlook. So, if you delete these OST files, that doesn’t make a difference due to the configuration. As soon as you open your Outlook account, it will connect to Exchange and start saving the emails as OST files.

Last Point for Summary

The OST files containing the data of Outlook account hold immense importance when it comes to a user’s official work. All the details of their business deals, or previous projects that might come in handy later are important for every business. Deleting these won’t be a great choice without making sure that they are saved some place safe as a backup which is why users ask is it safe to delete OST file and similar queries.


By Ashwani Tiwari

I am an Expert Technical Analyst, specialized in assisting users with complex technological challenges. Through my blogs and articles, I offer expert guidance to help tackle these technical issues effectively. My true passion lies in providing valuable insights and simplifying complicated technicalities, enhancing user understanding and confidence.