Everyone knows that Microsoft Outlook also uses an OST file (.ost) for offline usage. When you create an Outlook profile, Outlook stores a copy of your information on your computer until it syncs to the server. This feature allows you to work offline when you aren’t connected to the internet or the server.
The functionality of the OST file might look easier. However, there is a major drawback too. Like any other computer file, an OST file is not immune to corruption. When corruption affects an OST file, the screen displays various error messages. One prominent error you might see is the inability to open the Outlook OST file, as shown below.
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Why OST files cannot be opened?
How to Fix the Error Cannot Open Outlook OST File?
Why OST files Cannot be Opened?
The reasons behind OST file corruption that lead to the “OST file cannot be opened” error include the following:
- Abrupt termination of Outlook results in OST file corruption and can make OST file inaccessible.
- The Outlook application itself may freeze or shut down abruptly, preventing Outlook from opening the OST file.
- Faults in network cards, cables, routers, and other similar devices cause intermittent connectivity, which affects Outlook’s functionality and makes it difficult to access.
- Bad sectors on the hard drive affect the functionality parameters and refuse to open Outlook data file.
- Unexpected power surge sometimes results in incorrect functioning of the OST file.
When severe corruption affects Outlook, it shows on the files stored in it and displays the error message “OST File Cannot Be Opened.”
How to Fix the Error Cannot Open Outlook OST File In Outlook 2021 and Other Older Versions?
Using the manual approaches explained below, you can fix the OST file issue, including the error that Outlook file OST cannot be opened.
Before heading to the next sections, let us try fixing the error with a few basic troubleshooting steps like-
- If the problem is with the connecting devices, it is recommended that the network connections and devices be checked to ensure that they are working according to the standards.
- Adding add-ins enhances Outlook’s functionality, but faulty add-ins may sometimes create more trouble. Therefore, find the faulty add-ins and disable them by launching Outlook in safe mode.
- To Start Outlook in Safe mode, just type Outlook/safe in the Run dialog box. Try saving and Sending, and if it works, a faulty add-in is the main reason behind the error.
The steps related to basic workarounds are described under solutions to the most common Outlook errors. If none of the above methods worked for you, follow the next method about repairing the OST file by converting it into a healthy PST file.
Method 1: Use Task Manager to stop the Outlook Related Processes
- Close the MS Outlook program.
- Right-click on the Taskbar menu –> Click on Task Manager.
- Go to the Processes tab. Search for Communicator, Lync, Outlook, or Ucmapi. If you find any of these processes, select it and click the End Process button.
Method 2: Disable the Outlook Cached Exchange Mode
- Close MS Outlook –> Go to the control panel.
- Click on the Mail option –> Select Email Accounts.
- Next, go to click on the Email tab.
- Now click on Exchange account and then on Change.
- Uncheck the Cached Exchange Mode option under offline settings and Enter Next to finish the process.
Method 3: Repair the OST File with ScanPST.exe
Microsoft provides the inbuilt OST and PST Integrity Check tools, ScanOST.exe and ScanPST.exe, which help to fix minor corruptions in Outlook data files.
Repairing corrupt OST file with ScanOST.exe could be an easy way to fix Outlook.ost cannot be opened error. However, this Outlook inbuilt utility is available only with Outlook 2007 and lower versions. Hence, starting with the next versions, Microsoft uses ScanPST.exe to check the integrity of Outlook data files, whether OST or PST.
Does ScanPST work on OST files?
Yes, you can repair the OST data file with the help of scanpst.exe. Whenever corruption prevents an OST file from opening, scanpst.exe is triggered automatically. This tool can open, view, and repair corrupted and damaged OST files.
First, you need to locate the tool to run ScanPST.exe. Find your Inbox repair tool and click on the Start button to initiate the scanning process. Finally, click on the Repair button to rebuild your Outlook profile.
Even after you repair the file using scanpst.exe, if you cannot fix the “OST file cannot be opened” error, you should understand that severe corruption has affected your OST file, preventing scanpst.exe from working on it. In that case, you can try deleting and recreating the OST file.
Delete and Recreate the OST File
To delete the OST file and recreate it, follow the below steps:
- If you know your OST file’s location, close Outlook and delete the OST from your system.
- If you are not aware of the location of an OST file, enter %LOCALAPPDATA%\Microsoft\Outlook\ in Windows Search and press Enter. You will be taken to the folder where the OST is located.
- After deleting the OST file, start Outlook. Outlook will automatically recreate OST on your system.
Difficulties with Scanpst.exe
- Scanpst.exe doesn’t guarantee data integrity and security
- It works well only for minor corruption
- The inbox repair tool works directly on the original Outlook data file; the chances of the OST file getting damaged are high
- Scanpst.exe stops working if the file is severely corrupted or large and consumes much of your time.
Even after you run scanpst.exe, if you still cannot fix the “OST file cannot be opened” error, you should recognize that severe corruption has affected your OST file, preventing scanpst.exe from working on it.
Therefore, we recommend converting the OST file to a PST file for an easier repair process and to resolve the “OST file cannot be opened” error without any hassle.
Repair Outlook OST File Not Opening By Converting OST to PST File
Why should you convert OST to PST?
In OST, data is stored in MS Exchange Server, and any problem with the server directly reflects on the OST file. Meanwhile, PST files are stored on the client’s hard disk. Even if a server fails, the user can easily access data in the PST file. OST files can be accessed only with Exchange Server, whereas PST is compatible with other servers. Once converted into PST, you can access your Outlook data from any server. Converting OST to PST helps return all the Outlook data, such as emails, calendar information, contacts, etc. Once the Exchange Server crashes, you cannot recover OST data until you repair it. To use the mailbox data of the OST file online, you can convert the OST file to PST format and access the data stored in Outlook.
SFWare Convert OST to PST is a proficient conversion tool capable of resolving severe OST file structure corruption by reorganizing OST data files into PST file format. Besides fixing the OST file error, the tool also recovers lost data from its attributes, such as emails, tasks, contacts, notes, RSS feeds, etc.
Download the software now and try it for free.
To fix the OST file that is unable to open. Download and install the SFWare converter software and launch the application.
1: On the main screen, two options are available: “Open OST file” and “Find OST file”
Open OST file: This option is to repair inaccessible, corrupt, or damaged Outlook OST files.
Find OST file: This option is used to find the OST file automatically.
2: If you do not find the OST file in the default store location, select a drive to search for it.
3: The software will start the OST to PST conversion and generate a healthy PST file. Select the destination to save the converted file.
After you convert your OST to PST, try to open the file and ensure that it is free from the “OST file cannot be opened” error.
Frequently Asked Questions
1: What causes the “OST file cannot be opened” error?
Several reasons can cause the error. A few of the main reasons include interrupted terminations while working on Outlook data files, connectivity issues that prevent access to the OST file, and bad sectors on the drive that also lead to errors.
2: How does ScanPST help fix OST file errors?
Yes, with the help of ScanPST (Inbox repair tool), you can fix minor problems in Outlook data files, including OST files. It is an inbuilt tool by Microsoft Outlook that fixes minor problems in Outlook data files.
3: Does recreating the OST file fix the “OST file cannot be opened” error?
Sometimes, even after you use the Inbox Repair Tool to fix the “OST file cannot be opened” error, the error won’t resolve. This happens because severe corruption affects the OST file, preventing scanpst.exe from working on it. In such situations, you can try deleting and recreating the OST file. This method will surely help you fix the Outlook OST file issue.
