Error Solved - OST File is in Use and Cannot Be Accessed in Outlook

Updated on April 21, 2020

Resolve error "Outlook OST file is in use and cannot be accessed" error easily with Remo OST to PST Converter Software. Click on the below download button to get the free version of the tool and convert the corrupt, and inaccessible OST to a healthy PST file in three simple steps. Download and try now for free!!!

Fix OST File is in Use and cannot be accessed

If Cached Exchange Mode is ON in Microsoft Exchange, a replica of mailboxes residing on the Server is created on the local machine with .ost extension. This 'cached mode' permits users to work offline in Outlook and improves the performance of Outlook.

When the Server comes back online, all the changes made in the local mailbox cache (.ost) will be synchronized with the mailbox on the Server. However, due to a problem with the OST file, sometimes, Outlook users may experience errors such as:

"The file C:\users\....username.ost is in use and cannot be accessed". Now, close any application that is using this file, and try again. You might need to restart your computer to get rid of this issue. Before we proceed on how to resolve this issue if the error is popping up even after restarting your computer, let's analyze the reasons behind this error.

When does "the file .ost is in use and cannot be accessed" error message occur?

This error can occur due to several reasons, but often appears when you try to "Share" or "Save" and "Send" MS Office file via applications such as MS Word, Excel, and MS PowerPoint. The error indicates that the Outlook OST file is being used by the other program, and closing it may resolve the problem. But, spotting out the particular program causing the error can be difficult for the users. This error also suggests users to restart the computer that resolves the issue most of the time.

But, it is not necessary that the OST file is being used by the other program, and there could be various other reasons that can lead to this error, such as:

  • Many users trying to access the same OST file (typically in the case of networked systems).
  • Synchronization issue between the OST file and the Exchange Mailbox.
  • Conflicting applications with Outlook.
  • Unauthorized access to the OST file.
  • Slow internet connection or unreliable network connectivity.
  • Processes such as Office Communicator 2005/2007, UCMAPI.EXE, LYNC, etc. running in the bckground

So, whenever the 'OST file is in use and cannot be accessed' error in Outlook pops up, you can try some manual methods to resolve the issue. But, you need to be very careful while fixing the issues manually, and it requires extra technical knowledge to do it. So, Remo OST to PST Converter is the best choice to fix the issue. This software automatically, and quickly converts corrupt OST file extracting all it's data into a PST file. Read on further to know how to resolve 'OST file is in use and cannot be accessed' error in MS Outlook 2016/2013/2010, and earlier versions.


Fix OST file is in use and cannot be accessed error with Remo OST to PST Converter tool:

Remo OST to PST Converter is trustworthy utility that converts any healthy or corrupted Outlook 2013 OST file into accessible Outlook PST file in matter of minutes. The software is repair come recovery application that can even recover mailbox from OST file along with recovering other Outlook attributes such as reminders, journals, notes, calendar items, contacts, etc.

This tool repairs all Outlook errors, Exchange server problems and other related issues without any complexity. Along with OST file, the software will help you in can't open PST file in Outlook 2013 with its simple and interactive graphical user interface. With the aid of Remo Convert OST to PST toolkit, you can even convert oversized, password protected and encrypted OST file to PST file without any trouble.

Detailed steps to fix .ost file is in use and cannot be accessed error

Download and install the tool in your Windows PC. Launch the software by double clicking on shortcut icon of your desktop. If you know the exact location of the .ost file, click on “Open OST File” and using “Browse” option select the OST file. Otherwise, click “Find OST File”, so that the software automatically locates your OST file. Now you have to select the desired location to save your fixed Outlook data file and click on “Convert”.


Other benefits offered by Remo Convert OST to PST

  • During repairing OST file is in use and cannot be accessed error the software does not modify the original OST file as it works in read-only mode.
  • Round the clock technical support is provided to resolve user queries.
  • Free demo version is available to estimate its efficiency prior buying the complete edition of the product. The demo edition safely converts the corrupt OST to a healthy PST file, and allows a free preview of the healthy PST file contents, thereby you can come to a conclusion about the efficiency of the product before purchasing
  • The software allows you to find and search the OST file.
  • Compatible to work on all latest version of Windows and Microsoft Outlook.

When it becomes necessary to convert OST to PST file?

  • When you mistakenly delete your mailboxes on the Exchange Server the data can be recovered by converting the OST files.
  • When MS Exchange server crashes you will not be able to access it and in most cases it will repeatedly display errors.
  • While performing MS Exchange maintenance, you cannot access your mailbox. But if any emergency arises to access the Mailbox items then you need to convert OST to PST.
  • By performing OST conversion, you can easily transfer data from one place to another. It is useful in case the organization is shifting or when you want to move data on a different device.