Resolved “OST File is in Use and Cannot be Accessed” Outlook

What Causes an “Outlook OST File Cannot be Accessed” Error?

Several factors can cause the “OST File Cannot be Accessed” error, including:

• Abrupt system shutdowns, program crashes, or mishandling can corrupt OST files, blocking access.
• If the OST file is in use or opened by some other process, then it becomes inaccessible.
• When the OST file size is more than the limit, Outlook will be unable to open or access it.
• A damaged or corrupted Outlook profile may stop the application from opening the OST file.
• Network connection problems may lead to synchronization failures, rendering the OST file inaccessible.
• If the OST file exists on a network drive or other location, deny permissions may prevent it from being opened.

Understanding of these causes can assist you in troubleshooting the problem efficiently and re-establishing access to your Outlook OST file.

How do I Fix an Error Code “OST File is in use and Cannot be accessed”?

To fix the error, we execute several methods, such as manual methods and professional methods. Execute each method cautiously to minimize any possibility of data loss or data breach.

1. Restart Outlook and Your Computer

This is usually the easiest and best method to fix the “Outlook OST cannot be accessed” error. Occasionally, background processes or system errors can hang the OST file, preventing access. By closing Outlook and your computer, you can free up any processes that may be conflicting with the file.

To restart Outlook:

1. If Outlook is running, just click on the X in the upper-right corner of the program to shut it down.
2. On Windows, you can search for Outlook from the Start menu or click the Outlook icon.
3. Reopen Outlook after which attempt to access the OST file once again. This should show you if the error is no longer there.

2. Fix Outlook OST Cannot be Accessed by Disabling Antivirus

Antivirus software may stop Outlook from accessing the mail server. Temporarily disable your antivirus software to see if it fixes the issue.

Firewalls may also block email traffic. Disable third-party firewalls or Windows firewalls to see if they are causing the issue.

To disable Windows firewall:

1. First, type Control Panel in the search box and hit Enter to launch.
2. Under the Control Panel, select the System and Security tab.
3. Here, click on Windows Defender Firewall from the Windows Defender Firewall section.
4. Now, click on Turn Windows Defender Firewall on or off.
5. Next, disable your firewall protection. Click on OK to implement the changes.

If you have third-party antivirus software or a third-party firewall running, temporarily turn it off according to the instructions provided by its manufacturer.

3. Check for Locked Processes

If you’re encountering the “Outlook OST cannot be accessed” error, one of the causes may be that the Outlook process is already ongoing in the background. These processes may be locking the OST file, making it inaccessible. By scanning for and ending these processes, you can correct the problem and regain access to your OST file.

How to terminate the session:

1. First, press the Ctrl+Shift+Esc button simultaneously to open Task Manager on your system.

Note: If Task Manager appears in a simplified version, click at the bottom on More details to open to the full version with processes.

2. After that, navigate to the Processes tab.
3. Search for Outlook-related processes, including:
   1. Microsoft Outlook
   2. Outlook.exe
   3. Winword.exe
4. These processes might be running even though you have already closed the Outlook window.
5. After you find the Outlook-related processes, click on them individually.
6. Right-click on the process and select End Task from the menu.
7. This will close any background processes that could be holding the OST file.
8. On Windows, you can launch Outlook by looking for it in the Start menu.
9. Finally, verify whether your error is resolved or not.

4. Fix Outlook OST Cannot be Accessed by Repair Outlook Profile

A damaged Outlook profile can lead to many issues, including connection issues. You can try repairing the Outlook profile to fix this.

How to repair Outlook:

1. First, type Control Panel in the search box and press Enter to launch.
2. Then, navigate to the Programs in the Control Panel.
3. Next, click on the Programs and Features option.
4. In the Programs and Features option, locate Microsoft Office.
5. When you choose Microsoft Office, click the Change button.
6. When you click Change, two repair options will be shown.
   1. Quick Repair
   2. Online Repair
7. Once you select Quick Repair or Online Repair, follow the on-screen instructions to complete the task.
8. After the repair is completed, restart your computer to apply all changes.

5. Fix Outlook OST Cannot be Accessed by Creating Outlook Profile

If the profile repair failed, rebuilding the account could fix the issue by setting the email settings from scratch.

How to recreate:

1. Download and open the Outlook application on your computer.
2. Next, navigate to File > Account Settings > Account Settings.
3. Here, select the email that causes the problem and click on Remove.
4. After removing the account successfully, click New to add the email account.
5. Then, provide your valid credentials to add your new account.
6. Finally, restart your computer to apply settings and resolve the issue.

6. Run Outlook in Safe Mode

Launch Outlook in Safe Mode is a troubleshooting method that can resolve the error. Safe Mode begins Outlook with a basic configuration of features and turns off add-ins, extensions, and customizations. Follow these steps to launch Outlook in Safe Mode and solve the issue:

To launch Outlook in safe mode:

1. First, completely close the Outlook application from your system.
2. After that, press and hold the Ctrl button and open the Outlook application.
3. A pop-up will appear asking if you want to start Outlook in Safe Mode. Click Yes to confirm.
4. Outlook will now launch in Safe Mode, and you will notice Safe Mode in the application window title bar.
5. Attempt to open your calendar, emails, and other information in Outlook.
6. If the OST file is available without any errors, then it’s probable that one of the add-ins or customizations was responsible for the problem.
7. If your OST file is synchronizing with an Exchange server or another mail service, watch the sync process to make sure that everything is working properly.
8. After you have located and fixed the problem, you can restore Outlook to its default mode.
9. To open Outlook in normal mode, open Outlook again but without holding the Ctrl keys.

7. Check Network Connectivity

A slow or interrupted internet connection can cause the “Outlook OST cannot be accessed” error by preventing Outlook from connecting to the mail server. This disruption stops synchronization, making the OST file inaccessible and causing issues with accessing your Outlook data.

How to check:

1. Make sure you are on the internet by opening a site or using any other online resource.
2. If you are connected to Wi-Fi, ensure that the signal strength is good. You can also try connecting using an Ethernet cable to determine if the problem is with the wireless connection.
3. If you’re connected to a VPN, try disconnecting it to see if it resolves the issue, as some VPNs may interfere with Outlook’s connection.

8. Fix Outlook OST Cannot be Accessed by Repairing OST File

Corrupted PST (Personal Storage Table) or OST (Offline Storage Table) files may lead to numerous Outlook problems, including search issues. The built-in Inbox repair Tool, ScanPST.EXE, can be utilized to repair problems in damaged data files.

How to Repair PST/OST Files:

1. First, close Outlook completely before attempting the repair process.
2. Then, find SCANPST.EXE (the Inbox Repair Tool), usually at:

C:\Program Files (x86)\Microsoft Office\root\OfficeXX\

3. Next, click on the Start button to initiate the repair process.
4. After scanning is complete, click the Repair option to correct any errors detected.

Fixing damaged data files can restore Outlook to its normal operation, including the search function.

9. Resolve Error with a Specialized Tool

If all the above steps fail, you can utilize an Exchange OST Recovery to restore the data from the OST file. This will prevent you from losing any valuable data. It scans and recovers data from highly corrupted OST files in minutes and provides a preview of recovered data before saving it. The tool is also ideal in the event of a corrupt data file causing an error. It is supported by Windows and Mac operating systems, ensuring flexibility for everyone.

By following these methods, you can resolve the “OST File is in use and Cannot be accessed” error and regain access to your Outlook data.

Conclusion

If you are looking for a quick fix to repair the MS Outlook error “Outlook OST cannot be accessed,” you can opt for a professional tool. However, you also have some manual steps that may work for you. If the email is severely corrupted, skip all manual steps and use the professional tool directly. This software resolves the error flawlessly and provides an immediate fix without any risk of data loss.

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