How To Fix Outlook OST File Cannot Be Opened Error

OST file is very helpful to solve the problem of interrupted or limited internet connectivity by allowing the users to work offline. With the help of OST file, users can draft emails, set reminders, etc. even if they have disconnected to the mail server. Later this Outlook OST file is synced to the Exchange server and the emails composed offline are sent when the connectivity is established.

Introduction to Outlook OST file cannot be opened

When you open your Outlook profile, you might get an error saying “.ost cannot be opened,” blocking access to the Outlook application. The OST file’s main purpose is to provide accessibility to emails, contacts, and calendar data even without a connection to the Microsoft Exchange Server.

The "OST cannot be opened 2016" error prevents you from viewing downloaded emails and stops synchronization between the server and offline emails.

Why Outlook OST file not opening?

You cannot access your OST file if an error message “OST file cannot be opened” is displayed when you try to open your Outlook account.

This can be due to various reasons and you might try opening the OST file by using various methods such as – starting Outlook OST file in Safe Mode, turning off Compatibility Mode, and so on.

But if nothing works out and the OST file still refuses to open. Then, this doesn’t mean that you cannot access the OST file. By making use of the Remo Convert OST to PST software, fixing the error Outlook data file cannot be opened is easy and quick.

Why OST File Cannot Be Opened?

• Improper installation of Outlook application.
• Outlook in use cannot be accessed error.
• Abruptly terminating Outlook when OST file is still in use.
• Interruption while sharing OST file across network.
• Synchronization error between OST file and Exchange Server mailbox.
• Outlook exchange server is deleted and your OST file is orphaned.
• Exit a broadcast group or organization.
• Improper way of importing OST files

Types Of Methods to Fix OST Cannot Be Opened Error

1. Manual Methods
2. Using OST to PST converter tool

How to Fix Outlook OST cannot be opened error using manual methods?

• SCANPST.EXE:
  Scanpst.exe is an inbuilt Outlook data file repair tool. Normally the OST file does not open due to corruption. In such cases, utilizing Scanpst can automatically fix OST file corruption.
  1) Locate and Open the Scanpst.exe tool by following the below path:
  a)For Outlook 2016, 2019 if the OST file is not opening, Scanpst.exe can be found in the following path:
  C:\Program Files (x86)\Microsoft Office\root\Office 16
  b)For Outlook 2013 if the OST file is not opening, Scanpst.exe can be found in the following path:
  C:\Program Files (x86)\Microsoft Office\Office 15
  c) For Outlook 2007 if the OST file is not opening, Scanpst.exe can be found in the following path:
  C:\Program Files (x86)\Microsoft Office\Office 12
  2) Click on the Browse option to select the corrupt OST file, and click the Scan button.
  3) Click the Repair option to start fixing the error OST cannot be opened.


If the OST file still does not open after being repaired by Scanpst.exe tool, then follow these simple methods:

• Check for Outlook erratic behavior in Task manager:
  Open task manager and check if any Outlook process is interrupting the OST file access. Terminate all Outlook related processes by right clicking on the Outlook process from Processes tab and select End task.
  Restart Outlook and see if the OST file is now opening.
• Find and terminate any Outlook add-ins obstructing OST file access:
  Third-party Add-ins are a great way to customize and modify your Outlook access. But they also can be the biggest challenges to access OST files. You can find enabled add-ins in the following path:
  File->Options->Add-ins->COM Add-ins, follow this path once you run Outlook as administrator. Uncheck any third party add-ins and check if the OST file can be opened now.

If you are still not able to fix the issue, then head over to the next method i.e., fixing OST cannot be opened error with the help of Remo Convert OST to PST tool.

Why Convert OST file to PST format while fixing Outlook OST cannot be opened error?

If you've tried all manual methods to fix the error and still can't open the OST file, the only solution is to convert it into the PST file format.

The OST file has limitations compared to a PST file. It cannot be opened from any Outlook profile. To open an OST file, Outlook must be configured with the exchange server's port settings and the exact account credentials matching the .ost file.

This makes it extremely difficult to repair or access an OST file from any location. When you try to retrieve local copies of emails from the Microsoft Exchange Server, you won't be able to access Outlook OST files.

The Remo Convert OST to PST tool can fix severe corruptions in the OST file structure. It safely converts the OST file data into the PST file format to make the Outlook data file accessible.

The converted PST file can then be easily imported to access all your emails, contacts, calendar, rules, attachments, folder structure, and more. Using the Remo Convert OST to PST tool to convert a corrupt OST to PST is the best way to resolve the error "OST file cannot be opened."

how to Fix Outlook Data File Cannot Be Opened Using Software?

A quick solution to fix “OST file cannot be opened” error is by using Remo OST to PST Conversion tool.

• Download, Install and Launch Remo Convert OST to PST software.



• Launch the software and select Find OST File to automatically select the OST file.



• Then provide the destination path to save the converted file and click Next.



• Finally, click on the Convert button to start the converting process.

Why choose Remo to convert OST to PST?

• Fix the password-protected file or encrypted file.
• Repair the sync errors due to large or inaccessible OST files
• The corrupt OST file is used as a reference and the data is replicated into a new PST file. Hence the original OST file remains untouched.
• Along with fixing the OST file error, the program also recovers its attributes such as emails, tasks, contacts, notes, RSS feeds, etc which are deleted or lost.
• Remo Convert OST to PST software fixes OST files which exceed the file size limit.