How to Fix OST is not an Outlook Data File? – Problem Solved!
Summary: Outlook shows an error notice, such as “OST is not an Outlook Data File,” when the OST file becomes unreadable and cannot be accessed by Outlook. We’ve covered the causes of the error and how to fix it without losing any data in this blog.
For a variety of reasons, Outlook OST files may become corrupted or unusable. Outlook displays the following error message when this occurs because it is unable to access or read the OST file:
“I am unable to open Microsoft Outlook. Outlook Window cannot be opened. The folder set is not openable. The file ABC@xyz.com.ost located at C:\Users\USERNAME\Local\Microsoft\Outlook is not an Outlook Data File (.ost).
Users are consequently unable to access their Outlook accounts and mailbox contents. In Outlook 2010, 2013, 2016, or 2019, this could happen at any time and without notice.
Causes of the Error “OST is not an Outlook Data File”
There are multiple reasons why an error could occur. It usually happens when the OST file is corrupted because of integrity problems brought on by one or more of the following:
- Extra large (oversized)
- Intrusion of malware/virus
- Difficulties in the synchronization of Outlook and Exchange servers because to a bad network connection or a broken encryption key
- System failure
- Unexpected or forced system shutdown
- Outlook must be forced to end.
- Faulty Outlook profile
Ways to Fix the OST File Error
OST files are not accessible or able to be opened from other Outlook accounts, in contrast to PST files. For access to the mailbox data in an OST file, authorization from the associated MAPI profile is necessary. Therefore, in order to extract mailbox contents from inaccessible OST files into PST format, including emails, attachments, contacts, notes, tasks, and calendar items, you’ll need CubexSoft OST to PST Converter.
After converting the unreadable OST file to PST format, exit Outlook and delete your existing Outlook profile. Create a fresh Outlook profile and set up your email. Next, use the transfer Export wizard to transfer the converted PST file into your freshly configured Outlook profile. The program can also be used to import mail items from inaccessible OST files straight into an Office 365 account, a live Exchange server, or an existing Outlook profile.
This is the simplest and most practical technique to fix the issue and retrieve the mail items from inaccessible OST files without compromising data integrity.
Alternatively, you can attempt to resolve the OST is not an Outlook Data File problem by using the manual techniques mentioned below.
IMPORTANT NOTE: Make a backup copy of your current OST file to an external drive or another disk volume before using these methods. You may always use CubexSoft OST Converter for Mac & Windows software to restore mail items from the backup OST file if the manual techniques are unable to resolve the error.
Manual Solution to Fix ‘OST is not an Outlook Data File’ Issue
#1. Restart after updating Windows
If there are Windows updates that need to be installed, some programs might crash or provide an error. Check for Windows updates by going to “Settings > Windows Update.” Restart the computer after installing the pending updates. After that, launch Outlook and see if the issue has been fixed. Proceed to the next technique if not.
#2. Fix Outlook Profile
An inaccessible OST file linked to a faulty Outlook profile may also cause this OST file problem. You can try using the Outlook account settings to repair your Outlook profile in order to fix this. These are the steps to follow:
- Access File > Account Settings > Account Settings in Outlook 2010, 2013, 2016, or 2019.
- Select your profile (account) by clicking the Email tab.
- Choose the Repair option by clicking.
- In the “Repair Account” wizard, adhere to the instructions.
- When finished, restart Outlook to see if the issue has been fixed. You might attempt making a fresh Outlook profile if not.
#3. Make a New Outlook Profile
The steps below can be used to fix the OST is not an Outlook data file error and build a new Outlook profile:
- Navigate to the Control Panel, type in “Mail,” then click.
- Select “Show Profiles.”
- After selecting “Add,” type the new profile name. Select “OK.”
- Provide a password, email address, and name in the “Add Account” wizard. Choose “Next.”
- Pick the newly created profile from the list of options, then click “OK” to enable “Always use this profile” or “Prompt for a profile to be used.“
- Select the updated Outlook profile after restarting Outlook.
- The Outlook OST file problem should be fixed as a result.
#4. Turn off the Cache Exchange Mode.
Offline Mode is also disabled when the Cached Exchange Mode is turned off. Although you won’t be able to use Outlook while offline, this can help you resolve the problem. Cached Exchange Mode can be enabled later, though. To deactivate Cache Exchange Mode, take the following actions:
- Choose your Outlook profile by going to File > Account Settings > Account Settings.
- Click Change, uncheck the option for “Use Cached Exchange Mode,” and then select “Next.”
- When a pop-up window shows, click “OK,” and then select “Finish.”
- After restarting Outlook, see if the issue has vanished.
#5. Rebuild the Outlook OST File
The inaccessible OST file can be removed or moved to a new location, allowing you to create a new one. To locate the Outlook OST file and either relocate or remove it from its default location, follow these instructions.
- Select File > Account Settings > Account Settings from the menu.
- Navigate to the Data Files tab and choose the OST file linked to your profile.
- Go to the “Open File Location” page. This brings up a new File Explorer window with the location of the OST file shown.
- End Outlook, select “Delete” from the context menu when you right-click the OST file.
- Launch Outlook now. This will resolve the issue and immediately build a new OST file.
NOTE: These only functions if the mail server has your email profile activated.
The Concluding Words!
A corrupted or damaged offline folder file (OST) can occur for a number of reasons. Nevertheless, you can fix this by using the manual techniques covered in this blog. That being said, utilizing a trustworthy OST File to PST converter program is the greatest approach to fix Outlook-related issues, such as “OST is not an Outlook data file.” The program can assist you in avoiding data loss and extracting every mailbox item from an OST file that is unavailable or orphaned into an Outlook PST file that can be imported. Furthermore, you can export and import the mail items from unreadable OST files straight into an Office 365 account, a live Exchange server, or an existing Outlook profile.
