OST or Offline Storage Table file is created when you configure your Outlook with Exchange Server or accounts like Outlook.com, Microsoft 365, or IMAP. This file is a cached copy of all the mailbox items, including emails, attachments, contacts, notes, and tasks, on the local system. It gets synchronized regularly with the mailbox on the server, when there is server and internet connectivity, to keep the data updated.
In case you face any issues with your OST file, then you can simply create a new file as it is a synchronized copy of items on the mailbox server. In this article, we will explain how to rebuild OST file without losing any data.
Why do you need to recreate an OST file?
Below, we have listed some common reasons for creating a new OST file:
- When Outlook fails to open or keeps crashing.
- If emails are not syncing properly with the server.
- When you notice missing or outdated mailbox items.
- If the Outlook data file (OST) won’t function properly due to corruption.
- When Outlook shows frequent synchronization or send/receive errors.
- When you experience slow performance or lag while accessing emails.
Ways to recreate OST File without losing data
You can use the methods mentioned below to recreate the OST file without losing data.
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Delete the existing OST file
An approach is to delete the OST file from the default location and Outlook then rebuilds it. Let’s see how:
- Close Outlook.
- Navigate to the OST file location. The default location is: \Users\<YourUsername>\AppData\Local\Microsoft\Outlook\
- Select the .ost file and press Delete.
- Confirm the deletion.
- Restart Outlook. It will create a new OST file and start syncing the mailbox items from the server.
Wait for syncing process to finish. This may take time, depending on the mailbox size.
Note: It is always suggested to take a backup of the OST file before deleting it.
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Move your OST File to another location
Another way to recreate an OST file is to move it another location. Here’s how:
- Before starting the process, close your Outlook.
- Now, go to the default location of your OST file.
- Select the OST file. Press Ctrl + X to cut the file.
- Go to another folder on your system. Press Ctrl + V key to paste the file into it.
- Now open Outlook.
It will automatically recreate the OST file at the default location (from where it has been moved) and start syncing your mailbox items from the server.
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Rename the OST file
Another way to recreate the OST file is by renaming it. When you changed the file name, Outlook no longer recognizes it and creates a new OST file automatically. Follow the steps below to rename and recreate the OST file:
- Firstly, close Outlook completely.
- Go to the default location of your OST file.
- Right-click on your OST file.
- Click on
- Add “.old” at the end of the file name (such as Outlook.ost.old), then start Outlook.
When you start Outlook, it will no longer be able to detect the OST file and will create a new OST file.
Once you’ve recreated the OST file, it is suggested to check the file for any missing emails or other mail items. You may not find the items that were not synchronized with mailbox server. If this is the case, you can recover those items from the backup OST file (you’ve moved or renamed above). But for this, you have to take the help of a specialized OST to PST converter tool, such as Stellar Converter for OST. This tool can help you search and extract the missing items from the backup OST file. It then allows you to save the items in a PST file. This file you can effortlessly import into your Outlook by using the Import and Export wizard. This way you can recreate the OST file without losing any data.
Conclusion
In this article, we have mentioned methods of recreating the OST file without losing the data. Nevertheless, you must take a backup of your OST file before recreating it. This will come in handy in case there are any items missing from the new OST file. For recovering the items from the backup OST file (which is in orphaned state), you can use Stellar Converter for OST – a powerful OST to PST converter tool. You can free download this tool to evaluate its features and functionality.
