Outlook.ost File Cannot Be Opened Error! Here’s Quick Way to Fix it

Microsoft Outlook stored the data in two file formats PST and OST. Personal storage table (PST) contains email messages, calendar events, tasks, notes and other items on the local machine. If you’re using an IMAP or POP account, then your account information is stored inside of an Outlook Data File (PST).

On the other hand, Offline storage table is an exact replica of Exchange server mailboxes which helps users to work in offline mode. If you’re using an Exchange account, the data is stored in the Offline Outlook Data File (OST).

Well, the OST file is very useful for the users by allowing the users to work offline. With the help of OST file, users can draft emails, set reminders, and so forth even if they get disconnected to the mail server. Later, this Outlook OST file gets synchronized to the Exchange server and the emails composed offline are sent when the connectivity is established.

But, sometimes these OST files are vulnerable to many issues. They eventually stop working and you might receive an error message stated “Outlook.ost file cannot be opened”. There could be many reasons for getting this error pop-up message. Let’s have a look at them.

What Causes of Error “Outlook OST File Cannot Be Opened”?

1. Abrupt termination of Outlook.
2. Synchronization error between Offline OST file and Exchange Server.
3. Outlook Exchange Server is deleted and OST file is orphaned.
4. Improper installation of MS Outlook
5. Improper way of importing OST files
6. Multiple users attempt for accessing same OST file at once.
7. Software conflicts during the run time in Outlook application.

How to fix Microsoft “Outlook.ost file could not be opened” Error Manually?

There are some of the manual tricks that can help the users to resolve the issue.

1: Disable Outlook Cached Exchange Mode

1. Close MS Outlook>> go to control panel
2. Click on Mail option>>select Email Accounts and then hit on Email Tab.
3. Now, click on Exchange account and then on Change.
4. Uncheck the use of Cached Exchange Mode option under offline settings.
5. Click on the Next button to finish the process.

2: Disable the Outlook Add-ins

Although add-ins are used to enhance the functionality of Outlook, but sometimes it creates problems when there is a fault in add-ins. Thus, disable the add-ins by launching the MS Outlook in safe mode. You can also start Outlook in safe mode by following the below-mentioned steps.

1. Go to the shortcut icon for Outlook application.
2. Now, press and hold the CTRL key and double-click the Outlook.
3. Click ‘Yes’ when a window prompt appears to ask you to start the application in Safe Mode.

3: Repair file by Using ScanPST.exe

Sometime outlook.ost file cannot be opened error occured due to corrupted OST file. so to resolve this issue you have to use scanpst.exe inbuilt file repair tool of Outlook. Usually, the OST file does not open due to corruption. In such cases, using Inbox Repair Tool can automatically fix minor corruption issues.

1. Locate and run the Scanpst.exe tool.
2. Click on the Browse to select the corrupt OST file, and click the Scan button.
3. Click the Repair button to start fixing the error OST cannot be opened.

Drawbacks of Manual Methods

1. Scanpst.exe tool completes the whole process in 8 phases, that makes the entire process very time-consuming.
2. The manual methods are only applicable if there are minor issues in the OST file.
3. There are chances of data loss if you skip any step.
4. It doesn’t guarantee data integrity and security.

Automated Method to Resolve Outlook.ost File Cannot Be Opened Error

If anyhow above-mentioned method did not fix this Outlook.ost file cannot be opened, then it means that your offline OST files are highly corrupted. And it is high time to use professional software. This OST repair tool is proficient software that can easily resolve all the Outlook OST file issues without any difficulties.

Why Choose Automated Tool Over Manual Methods?

The secure and reliable way to fix the Outlook 2019, 2016, 2013, 2010, 2007, 2003 .ost file cannot be opened error (due to .ost corruption) is to use this above-mentioned tool. Some of the benefits of using this proficient tool are as below:

1. Quickly repair corrupted or damaged files without any data loss.
2. Provides an option to save the OST data file in multiple formats.
3. Generates export reports to save recovery information.
4. Maintain folder hierarchy structure.
5. Outlook installation not required to perform repair task.
6. Compatible with all versions of the Windows operating system.

Final Verdict

In this blog, we tried to resolve this Outlook.ost file cannot be opened error. So, we mentioned some of the manual methods. But, if your OST file is corrupted & you receive outlook.ost file could not be opened error then you have repair file to fix this issue.