How to Fix OST File is in Use And Cannot be Accessed Outlook 2016?

admin ~ Modified: 04-04-2020 ~ Microsoft Outlook , Technology ~ 5 Minutes Reading

Fix Outlook OST File is in Use And Cannot Be Accessed Error

The Exchange mailbox may contain important conversations and dialogue with clients and customers. Often there are problems in Outlook that can prevent users from opening and checking their mail. There is a common error that says something like ‘The File Username.ost Is In Use and Cannot be Accessed’. A lot is not known about it and hardly any relevant information available online. This article will help all those having the ost file is in use and cannot be accessed on their system. They can read all about it and try the solutions mentioned in this post.

‘I tried to save a Word document and select ‘Save and Send’. This should normally have triggered a response where my document is attached to an email in Outlook. But I get this error saying ‘The file .ost is in use and cannot be accessed’. It asks to restart computer which is odd as I was just using my account to send and receive emails. The same thing has happened with some of the other employees in our company. Does anybody have a proper solution for this?’

Reasons – The File Username.ost Is In Use and Cannot Be Accessed Error

There can be a number of factors contributing to this inability to read ost file is in use and cannot be accessed. Here are some of them listed below:

  • Synchronization issue between server and Outlook offline data file(.ost)
  • Another application using the OST file like antivirus, file scanners etc.
  • Bad internet connection or a slow network
  • Interruption from processes like LYNC, Communicator, UCMAPI
  • Trying to work with an unauthorized .ost file
  • Unable to access OST file saved on a network drive
  • Unnecessary add-ins that may be blocking access to the mailbox

Also Read: How to Fix Outlook Not Responding Error?

How to Fix the .ost File is in Use and Cannot be Accessed Outlook 2016 Manually?

Following are some of the techniques that can be used to fix the ost is in use and cannot be accessed 2016:

Solution#1 Quit All Outlook Related Processes

  • First, exit the email client and open Task Manager.
  • Then, go to ‘Processes’ tab and look for names like ’Lynk’, ‘Communicator’ and ‘UCMAPI’.
  • Then, select each one at a time and choose to ‘End Task’ to repair OST file.

Solution#2 Disable Exchange Cached Mode

  • First, go to Control Panel>>Mail>>Email Accounts>>Email.
  • Then, choose the appropriate email address and click on ‘Change’ button from the navigation bar.
  • Then, mark the ‘Use Cached Exchange Mode’ to fix OST file errors.
  • Finally, click on the Next and then the Finish button.

Solution#3 Remove Add-ins

  • First, launch Outlook and go to File>>Options>>Add-ins to repair  file.
  • From the ‘Outlook Options’ window, select ‘COM Add-in’ under Manage header and click Go.  
    ost file is in use and cannot be accessed
  • Then, add and remove the add-ins and retry sending the Word document.

Solution#4 Outlook in Compatibility Mode

  • First, find the Outlook.exe icon and hold down the Ctrl key and double-click on it.
  • Finally, confirm the dialogue box that asks for confirmation in order to fix OST file.

Solution#5 Use ScanOST.exe to Fix the file username.ost is in use and cannot be accessed

  • This is an inbuilt tool provided by Microsoft to remove any error in the offline data file.
  • First, go the folder where the Outlook.exe file is saved. There locate the ScanOST.exe file and double click on it.
  • Then, select the Exchange profile from the list and click ‘Repair Errors’ and ‘Begin Scan’ to fix OST file.

An Alternate Choice to Fix OST File Error Message Outlook.ost is in Use and Cannot Be Accessed

These are just too many confusing steps which may be technical jargon for some users. They look for workarounds that may allow them to open and read emails from their Outlook mailbox. One such professional software is the Revove OST File Recovery. It is easy to download and use on any Windows system. The demo version is available for free that can be used to repair, recover and convert up to 25 items/folder. It can even work with NST file format. This application is compatible with Outlook 2019 and below versions.

Free Download Outlook PST File Repair Software

Technology is ever-changing and updating itself. It is difficult to keep up with all the new errors and solve them manually. Even experts search for solutions online in many cases. For one such issue: ‘OST file is in user and cannot be accessed error’ resolution steps are described here. There are methods that can be implemented by applying simple techniques that help in regaining access to the mailbox. There are frequent bugs and issues that occur regularly in any organization. Solving them each time may be quite hard for the help desk and support teams. These companies can go for the third-party tool mentioned at the end of this post. It is a user-friendly and cost-effective way to ensure quick recovery even in case of high-level corruption.