How to Convert OST to PST Format?

Offline Storage Table (OST) and Personal Storage Table (PST) are both file formats used by Microsoft Outlook. These files help synchronize your emails and notes etc., on your local storage. While OST files are encrypted and restricted to their parent outlook file, PST files offer improved access and importing options. Thus, it is often preferred to convert OST to PST files.

Not sure how to convert an OST to a PST file? In the following read, you can learn about the benefits of converting your OST file to the PST format. Also, discover trouble-free methods to convert OST to PST instantly and what to do if your PST file goes corrupt.

Why Do You Have to Convert OST File to PST?

Wondering what good converting your OST file to PST format can bring you? The process to convert OST to PST serves various benefits to users. Following is a list of the primary reasons you should consider converting OST to PST files:

1. Reduce OST File Size

If the OST file size is considerable, it can give rise to integrity issues. A large file size means your OST file will be more likely to corrupt. You can transfer your older data to a PST file format to avoid this issue. Doing this will effectively reduce the size of the OST file, and you can easily access this data on your PST file.

2. Crash of Exchange Server

Often, the Exchange server crashes due to power failure or virus and malware attacks. If this occurs or the server goes under maintenance, it becomes challenging to access data stored in the OST file from the mailbox server. Under such circumstances, you can convert OST to PST files. This will help you access your data from another Outlook profile.

3. Data Migration

Converting your OST file to PST can also prove helpful when you are moving your data from one place to another. Because you cannot directly transfer OST files to another system, it is easier and safer to convert OST to PST and then migrate data.

4. Avoid Data Loss

Outlook errors such as synchronization errors and not being able to receive emails are relatively common. Troubleshooting these errors is easy but can jeopardize your data. If this occurs, you can create a backup of your OST file in a PST format. This will help avoid any significant data loss from your system.

5. Manage Orphaned OSTs

If your Exchange profile is inactive or disabled from the server, it will stop the synchronization process from the mailbox to the server. In such an instance, the OST file is called an orphaned file. To avoid this, you can convert the OST to PST format to protect your data and access it on your local device.

Three Free Methods You Can Use to Convert OST to PST File

Are you wondering how to convert an OST to PST format easily? There are several methods available that can get the job done for you. The following techniques are the easiest ways to convert an OST to a PST file without going through much trouble:

Method 1: Exporting Your Mailbox as PST

Exporting your mailbox in a PST format is one of the simplest and most effective methods to convert OST to PST. You can do this by following the simple steps mentioned below:

Step 1: Log in to Outlook using your Exchange account and go to the “Files” tab. Locate and tap on “Open & Export” and select the “Import/Export” option.

tap on import export button

Step 2: From the dialogue box that pops up, tap “Export to a file” and hit “Next.” Now select the “Outlook Data File (.pst)" option and hit "Next."

select pst file and next

Step 3: Now, select all the folders that you want to export. After that, you now need to select the folder where you wish to export your file. Select a folder and click on "Next." Now browse the location of your choice and tap "Finish" to export your file.

select the save location

Method 2: Efficiently Archiving OST Emails to PST

Outlook offers an AutoArchive option using which you can save the emails from your OST to a separate PST file. This option can also help efficiently reduce the size of your mailbox. To activate this option, follow the below instructions:

Step 1: Open the "File" tab on Outlook and click on "Options." Tap on “Advanced” and select “AutoArchive Settings” from the left panel.

select the save location

Step 2: Choose the number of days for the auto-archive process from the pop-up dialogue box. Now select the folder where you want to save the archived PST files. Look for any additional archiving option you wish to modify, and click on "OK."

finish settings and tap ok

Method 3: Converting OST Using Cleanup Tools to Move Mails to PST

Using Cleanup Tools on Outlook, you can move your mails from an OST file to a PST file. Doing this can help reduce the chances of errors occurring and reduce the original OST file size. To achieve this, follow these steps:

Step 1: Launch Outlook on your computer and go to "File." From there, click on "Info."

Step 2: For Outlook 2010 and 2013 users, click on "Cleanup Tools" and select "Archive." If you are using Outlook 2016 and 2019, you can go to "Tools," and then select "Clean Up Old Items."

access cleanup tools

Step 3: From the pop-up window, check the "Archive this folder and all subfolders" box. Now select the folder you want to archive and choose a specific date. You can also choose the archive file location, and when you click on "OK," all the mail items until your specified date are archived in a PST file.

archive the selected folders

Limitations You Can Face While Converting OST to PST through Manual Techniques

While the process to convert OST to PST is relatively easy and beneficial, it does not perfectly go every time. Here are some instances where manual techniques make it difficult to convert an OST file to a PST format:

1. Corrupted OST Files

Outlook does not allow the opening or modification of corrupted OST data files. If your OST file has gone corrupt, you cannot replace or convert it into a PST file through manual methods.

2. Different Exchange Account

A converted OST file can only be accessed using the same Exchange user account used to create it. If you are using a different account to open the file, you will not be able to access its contents.

3. Technical Specialties

Manual methods of OST file conversion are best suited for users with enhanced technical expertise in data transfer. If you are not a tech-savvy person or new to Outlook’s interface, the manual process can prove troublesome.

4. Orphaned OST Files

If your OST files are not connected to the Exchange server, they become orphaned files that you cannot manually convert to a PST format. Only those OST files linked to your Exchange server have a shot at manual conversion.

Bonus Tip: Repair Your Corrupted PST File with Stellar Outlook Repair Tool

While PST files are great for reducing your OST file size and avoiding data loss, they are still prone to corruption. PST files often become the corruption victims during the format conversion process. You can save your data using a data repair program such as Stellar Outlook Repair Tool if this happens.

Stellar is an efficient tool that can help you recover all of your essential data from a corrupted PST file. Using this tool, you can save emails, attachments, contacts, tasks, calendars, and more. Stellar offers a powerful repair solution, including deep scans and ample file size support. You can also recover data from an encrypted PST file using the Stellar Repair Tool.

Here is a step-by-step guide on how to repair corrupted PST files using Stellar Repair:

Step 1: Locate your PST File

Open Stellar Repair for Outlook on your computer. You can click on “List Profiles” to let Stellar automatically scan for data files. To browse your PST file manually, click on the “Choose Manually” option.

select choose manually option

Step 2: Initiate Repair Process

Select your data file and tap on "Repair." Stellar will now begin to repair your data file. Once a "Repair Complete" message appears on the screen, you can preview the repaired files.

tap on repair button

Step 3: Select the Output Format

Now select the items you wish to recover. Go to the "Home" tab and select "Save Repaired File." In the "Save As" pop-up window, choose the output format as "PST" and hit "Next."

select the pst output format

Step 4: Save your PST File

Now select a location where you wish to save your recovered file and click on "OK." Stellar will protect your new PST file with recovered data on your computer.

export the repaired pst file


Although OST and PST are both utilized as Outlook data files, the PST format serves a significant advantage over OST files. PST files can help prevent data loss and offer increased access in the event of unprecedented file corruption or server failure. Thus, you need to know how to convert an OST to a PST file.

You can easily convert OST to PST with a few simple clicks using the methods mentioned above. You might face a few limitations during the manual conversion process, but it is worth taking a shot. Moreover, using the Stellar Outlook Repair Tool, you can now repair your corrupted PST file seamlessly without losing important data.