Two Free Methods to Convert OST to PST File

Aftab Alam
Aftab Alam | Updated On - 28 Mar 2022 |

Read time 9 minutes

Cached Exchange mode was introduced by Microsoft to overcome the difficulties like Exchange downtime and unavailability.

Microsoft Outlook, in the offline (Cached Exchange) mode, saves all the Exchange mailbox data in a local file named OST file or Offline Outlook Data file. The changes made by the user in the offline mode are later updated to the server mailbox when the Exchange connection is re-established. As the OST file resides on the user’s computer, it is unaffected by Exchange Server crashes and disasters, Exchange mailbox deletions, etc. So, Exchange administrators and end-users can use OST files to restore user mailbox data on the occasions of such eventualities.

Here are some situations when converting an OST to PST files becomes very helpful:

OST files contain unsaved user mailbox data. So, they are useful in situations like:

  • A few user mailboxes get deleted from the Exchange server
  • Want to back up a few Exchange mailboxes (before the deletion of mailboxes)
  • An Exchange user wants to rebuild his corrupt OST file, but the user has some unsaved data in the OST file
  • EDB files are inaccessible due to Exchange corruption, Server crash, etc. but users want their emails urgently
  • To re-establish email communication during Exchange downtime or unavailability

Instant Solution

Try automated tool Kernel for OST to PST Converter to Convert OST File to PST, EML, MSG, Office 365, and Exchange.

Buy OSt to PST converter Tool

There are multiple methods to convert any OST file into PST provided you can log in to Outlook with the same Exchange profile. Some native methods to convert OST to PST are presented here:

Method 1: Export mailbox as a PST file

Login to Outlook with the Exchange account that was used to create the OST files. And to export the OST mailboxes to PST, follow the simple procedure as given here:

  1. Go to Files >Open & Export and click Import & Export.Import & Export
  2. Select Export to a file; then click Next.Select Export to a file
  3. Select the second option—Outlook Data File (.pst)—and click Next.Select PST file
  4. Select the folder(s) which you want to export and click Next.Select the folder to export
  5. Note: You have the option to include subfolders as well.

  6. Browse the location where you want to save the new PST file 5. and choose an option regarding the duplicate items.

Note: There is an optional choice to provide a password to the PST file, but you can easily move ahead without choosing it.

Method 2: Use ‘Archiving’ to save OST emails to PST

By enabling the Auto Archive method in Outlook, you will be able to save the items of the OST file in a separate PST file. This method helps you to keep the size of your mailbox manageable. When there are many older messages and you do not require them in the mailbox, you can put them in the archive folder easily. This will reduce the size of the mailbox. Follow the simple steps to enable auto archiving in Outlook.

  1. Launch the Outlook application, go to File, and click Options.
  2. Go to Advanced and click Auto Archive Settings.Auto Archive Settings
  3. Now select the number of days in which you want to run auto archiving. Select the folder to save the archived file; also, provide the archiving options and finally click OK.Select the folder to save the archived fileWith this, mailbox items from your OST file will be saved to the PST file as per your archiving settings.

Convert OST to PST without Exchange profile or server connectivity

Kernel for OST to PST Converter is a professional tool that can freely convert 25 items from each OST folder to PST. Its advantage is that it can convert offline OST files to PST without an Exchange profile or Exchange Server connectivity. It has a highly user-friendly interface that lets the user select OST file(s), recover items including the deleted ones, and convert them to PST format. Also, it can convert multiple OST files to PST at a time. Let’s see the working of the tool:

  1. Open the OST to PST tool. It will open a wizard to select single or multiple OST files. Select the OST file from its location.Select the OST file
  2. When the tool displays the OST file content, you can choose a folder and view its content in the preview pane. To convert the OST file into PST, click the Save option on the toolbar.Save option on the toolbar
  3. To save in PST, click PST file (MS Outlook) as the Output in PST
  4. Select and apply the required filters – From, To, Subject, Folder Name, Item Type, and Date rangeSelect the filters
  5. You have the option to split the PST file after a certain size. Provide the required details.Select option to split the PST
  6. Browse 6. the destination and provide the required details. Lastly, click Finish.Browse the destination
  7. When the conversion is complete, the tool shows a message showing the PST file name and its location.conversion is complete

You can manually convert OST to PST files only when you are using Outlook with the original Exchange account. But the software converts even inaccessible OST files into PST format without the original Exchange profile and Exchange Server connectivity. It can convert OST files created by webmail (IMAP) accounts too. Also, it provides many advanced filtering and saving options.



The blog has proposed and explained different ways to convert OST files to PST files such as archiving OST files, exporting OST files to PST with Import/Export function in Outlook, and quick, efficient, automated conversion via a professional OST Conversion tool. This conversion is helpful in multiple situations including when the server is crashed or has become unavailable. With this tool, you can fetch the OST data very easily.


Q. Does the software work differently for different types of files? Can you mention the software process in simple steps?

A. The functional process of software is the same for repairing either a single or multiple OST files, and it gives a clean preview also. But the saving process is different as per the chosen destination by the user-
1. In the software’s Home Screen, click the Browse option to select the OST files.
2. Choose the OST file from its saving location where it has resided.
3. Start Scanning the software after selecting the files.
4. Check the recovered items in preview mode. You can choose any item, and its preview will come up automatically.
5. Choose the destination and apply the filters using the destination file.
6. Choose the saving folder for the destination file.

Q. Does this OST Converter tool support the conversion of very large OST files to PST?

A. Yes, it does. It can easily convert OST files of any size to a PST file without file size limitations. While saving, the tool allows you to specify a size after which a PST file will be split, making it easier to manage.

Q. When I convert OST File to PST, will my OST data be changed in any way?

A. The software scans your file and performs a simple recovery of the whole data without affecting the integrity of the file. This tool will keep all the mailbox properties and hierarchy intact after PST conversion.

Watch Video: To View the complete process of OST to PST files Conversion