How to rebuild OST files in Outlook 2019, 2016, 2013 and 2010?

What is the need to recreate an OST file?

An OST file is a data file in Outlook that stores a local copy of mailbox items, including emails, contacts, calendars, notes and attachments. It's created when Outlook is set up with an Exchange, Office 365 or IMAP account, enabling you to access your mailbox items even when you are offline. The changes made to the OST file are synchronized with the mail server once the internet connection is restored.

However, various events like system crashes can cause OST files to become damaged, making them inaccessible to Outlook. This results in Outlook synchronization issues and error messages. Although you can recreate or rebuild a new OST file to fix this issue, it may lead to data loss and missing mail items that are not synchronized with the mailbox on the email server.

Rebuild Outlook OST file

When your Offline Outlook Data File (OST) becomes corrupt, you will no longer be able to access your mailbox data. Though you can sign in to your live mailbox in a web browser and access your emails from the Outlook Web Application (OWA), you must first recover or rebuild the Outlook OST file if you want to access your local mailbox data offline.

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How to open an OST file?Convert orphaned OST file to PST Convert encrypted OST file to PST Restore deleted emails from OST Export emails and calendars from OST Outlook cannot connect to server Office 365 Outlook errors have been detected

OST file may get corrupted and become inaccessible in some of the following cases

If the size of the Outlook OST file exceeds the specified limit.
Malware or virus infection: Malware or virus infections can corrupt files, including the OST file. If your computer is infected with malware or a virus, it can cause the error message.
Large OST file size: If your OST file is too large, it can cause Outlook to become unresponsive or crash, leading to the error message. Splitting the OST file into multiple PST files is a good solution in such cases.
Hard drive issues: If your hard drive has bad sectors, it can cause corruption to the OST file and other files on your computer.

How to recreate OST File in Microsoft Outlook 2019, 2016, 2013, 2013 and 2010?
Although the OST file corruption can be resolved by recreating or rebuilding a new OST file, it frequently results in missing mail items and data loss because the new items may have not synchronized with the email server's mailbox. As a result, rebuilding an OST file while avoiding data loss requires a methodical approach.
- Method 1: Rebuild an OST file by enabling the Cached Exchange Mode
  The Cached Exchange mode enables an offline copy of the Exchange server’s mailbox on your computer in the form of an OST file. The following steps describe how to enable Cached Exchange Mode in Outlook.
  - Step 1: Open Microsoft Outlook and go to the File menu
    Click on the ‘File’ menu in the top left corner of the Outlook window.
  - Step 2: Select the Outlook Account Settings
    From the drop-down menu, select ‘Account Settings’ and then choose ‘Account Settings’> again.
  - Step 3: Enable the Cached Exchange Mode for your email account
    Select the email account that you want to recreate the OST file for and then click on ‘Change’.
    In the Change Account window, check the box that says ‘Use Cached Exchange Mode’ and click ‘Next’.
    Click ‘Finish’ to complete the operation.
  - Step 4: Close and relaunch Outlook to recreate the OST file
    Outlook will automatically create a new OST file for the email account that you selected in step 4.
- Method 2: Rebuild an OST file in Outlook 2019, 2016 and 2013
  You can also recreate an OST file by renaming or moving the existing OST file from its location. Before you rename the OST, ensure that you copy and take a backup of the file.
  - Step 1: Close Microsoft Outlook if it is open.
    Close Outlook and make sure it's not running in the background.
  - Step 2: Navigate to the location of the existing OST file.
    The default location is usually in the following path:
    C:\Users%username%\AppData\Local\Microsoft\Outlook\
    You can also locate the OST file by going to File > Info>Account Settings > Account Settings > Data Files > Open File Location.
  - Step 3: Rename the existing OST file
    Locate the OST file you want to recreate and rename it with a different file extension. For example, change the extension from .ost to .old.
  - Step 4: Relaunch Microsoft Outlook to rebuild the OST file
    A new OST file will be automatically created and start synchronizing with the Exchange server.
  See steps to rebuild an OST file in older versions of Outlook (2013, 2010, 2007 and 2003)
  Limitation: When you rebuild the OST file with this method, any changes saved in the local OST file are completely lost. For instance if you have missing emails that were not synchronized with the Exchange server, you will not be able to recover these mail items. In order to restore any email data or deleted items from the OST file, you must convert the OST to PST.
- Method 3: Rebuild an OST file with EdbMails OST repair tool
  EdbMails OST to PST converter tool can help you recover and rebuild the OST file from corruption and supports all the OST files from Outlook 2019, 2016, 2013 and Outlook 2010. EdbMails quickly recovers the entire OST file and converts the OST to PST file which is useful to rebuild your corrupt OST file. You can then import the PST file into Microsoft Outlook to restore your mailbox data.
  Steps to rebuild and convert the OST to PST
  - Step 1: Install EdbMails OST to PST software tool
  - Step 2: Select the corrupted OST file that you want to rebuild
  - Step 3: Preview and select the emails and folders for export
  - Step 4: Export the rebuilt OST file to PST.
  - Step 5: Import the PST file into Outlook to restore all mail items.

Advantages of EdbMails for rebuilding an OST file

Automated Mailbox Recovery: EdbMails can perform automated recovery of corrupted OST files and is capable of restoring all your mail items from a backup snapshot of an OST file. See how to backup Exchange mailboxes with OST files.
Easy-to-use Interface: EdbMails has a user-friendly interface that simplifies the recovery and export operation without requiring any technical expertise.
Efficient Scanning: EdbMails uses advanced algorithms for scanning and repairing the corrupted files and can even perform granular OST recovery of all the mail items.
Customizable Recovery: EdbMails offers several customizable options for recovery, such as selective recovery of emails, contacts, calendars with its advanced include and exclude filters.
Fast and Secure: EdbMails performs the recovery process quickly and securely without compromising the data. It maintains complete consistency and email formatting during recovery, export and migration operations.
No File Size Limitations:EdbMails can recover OST files of any size and can also export an oversized OST file into multiple smaller PST file sizes.
Multiple Export Options: EdbMails provides multiple export options such as OST to PST, HTML, EML, MHT and can even help you import OST to Office 365 and Live Exchange.

Frequently Asked Questions (FAQ)

How to create an OST file in Outlook 365?
When you connect Outlook to a Microsoft Exchange account, an OST file is automatically created and used to store a local copy of your mailbox data. However, if you need to manually create an OST file in Outlook 365, you can follow these steps:
- Step 1: Open Outlook 365 and click on the ‘File’ tab.
- Step 2: Click on Account Settings and then click on Account Settings again.
- Step 3: Click on the Data Files tab and then click ‘Open File Location’
- Step 4: Note down the location of the OST file and close Outlook
- Step 5: Rename the OST file and relaunch Outlook to rebuild the file
Note: You may need to enable Cached Exchange Mode in Outlook to create an OST file.
How to rebuild the OST file if I am not able to access Outlook?
You can rename the OST file and relaunch Outlook to rebuild a new OST file. However, if you want to rebuild an old OST file without losing any of your email data, you can use EdbMails OST to PST converter to recover the OST file and convert it to PST.
Can an OST file be repaired?
Yes, an OST file can be repaired using various methods. Microsoft Outlook provides an inbuilt repair tool called 'Scanpst.exe' to fix minor OST file issues. However, if the corruption is severe, it may not be able to repair the file. In such cases, third-party tools like EdbMails OST to PST converter can be used to repair the OST file and recover its contents. EdbMails can recover data from corrupted, encrypted, password-protected, and inaccessible OST files.

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Rebuild an OST file

Rebuild OST file from Outlook 2019, 2016, 2013 and 2010

What is the need to recreate an OST file?

OST file may get corrupted and become inaccessible in some of the following cases

How to recreate OST File in Microsoft Outlook 2019, 2016, 2013, 2013 and 2010?

Advantages of EdbMails for rebuilding an OST file