What to Do If OST Files Are Inaccessible in MS Outlook 2016 and 2019?

What to Do If OST Files Are Inaccessible in MS Outlook 2016 and 2019?

The PST and OST files are extremely important for the proper functionality of the MS Outlook account. The OST files, also known as Offline Storage Table files, might become inaccessible due to various hardware and software-related reasons. This might cause MS Outlook to function improperly. Therefore, if you’re facing problems accessing the MS Outlook OST data files or facing other types of errors while accessing the OST files, you need to use the Inbox Repair Tool or ScanPST tool. But the ScanPST tool is only effective for minor corruption. If the OST files are severely corrupted, you need to use third-party MS Outlook recovery software to repair the damaged or corrupted OST files. 

Reasons for OST File Corruption 

Various reasons might lead to OST file corruption. Depending on the reason, the OST files might face minor or severe corruption. Here are some of the common causes you need to know:

  • Software or antivirus conflicts. As per Geeks for Geeks, anti-virus can slow down your system. 
  • Connectivity issues 
  • Unexpected power failure 
  • Bad sectors or system crash 
  • Improper MS Outlook add-ins 
  • Synching errors 
  • Improper termination of MS Outlook 
  • Force shutdown 
  • Damages MS Outlook application 

But some effective methods will help you repair the corrupted OST files. But before you implement any type of repairing methods, make sure you take proper backup of the OST files as the manual methods might cause data loss. The only exception is the third-party software as these tools won’t cause any data loss. 

If you don’t want to face the hassles of troubleshooting the OST files, consider using the DataNumen software recovery tool to convert the OST files to PST files and quickly recover the data items. The DataNumen outlook repair tool will undoubtedly help you a lot in such situations. But if you want to follow the manual method, make sure you remember these steps:

Restart the MS Outlook Application 

Restarting the MS Outlook application will help you solve the corruption. Consider rebooting the system and then launching the MS Outlook application. This might solve the problem. But if you’re still facing problems accessing the OST files in MS Outlook, you need to follow the next method. 

Disable the Faulty Add-Ins 

A damaged or faulty add-in can cause additional damage to the MS Outlook OST files and might lead to numerous errors, such as OST files cannot be accessed or opened error. In such situations, you need to disable all the add-ins and troubleshoot the application. If you know the specific add-ins that are causing the problem, you can remove them from your system. Here are the steps you need to follow:

  • Close the MS Outlook application and then launch it in safe mode. Hold the CTRL key and then double-click on the MS Outlook application. 
  • Once it opened in safe mode, you need to disable all the add-ins. And then restart the MS Outlook application. 

If this solves your problem, enable one add-in at a time and pay close attention to observe when the error appears. This way you can remove the faulty add-ins from your system. 

Disable the Cached Mode 

This is one of the most effective manual methods that will help you solve MS Outlook corruption. Cached Exchange Mode will develop a local copy of the mailbox items that are stored on the MS Outlook server. But when you disable the Cached Exchange Mode, you will be able to fix this issue. These are the steps you need to keep in mind:

  • Open the MS Outlook application and go the File> Account Settings> Account Settings 
  • Click on the profile of MS Exchange and choose the option Change 
  • You will see an option Cached Exchange Mode from the Offline Settings. Uncheck this option. 
  • Restart the MS Outlook application and see whether the problem has been solved or not. 

Check the Other Programs 

Sometimes, other third-party applications in your computer might be the reason why the OST files are facing corruption. This is why when you try to open the MS Outlook application; you will receive numerous error messages. Therefore, you might need to stop the background MS Outlook processes as well as other third-party application conflicts. Here are the steps you need to follow:

  • Close the MS Outlook application safety and then go to the Task Manager from Taskbar. 
  • Find the option Processes that will be visible on the tab. 
  • Search for the option ‘Outlook’, ‘Communicator’, and ‘Lync’. 
  • Choose all of these processes and click on the End Task option. 

Use ScanPST Tool 

As mentioned earlier, the ScanPST or Inbox Repair Tool might help you fix the OST file corruption or MS Outlook corruption. The ScanPST tool will be installed on the directory. This tool will help you fix different types of MS Outlook data files. 

However, you need to find the tool first. Additionally, it’s only effective for minor corruption. 


These are things you need to remember if the OST files are inaccessible. Do you have any other questions? Make sure you let us know. 


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