How to Fix “Username.ost is in use and cannot be accessed” Error in Outlook 2016?

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An OST file is a replica of user mailboxes on Exchange Server, which is saved on the system. These files are known to have different errors or issues like “OST is in use and cannot be accessed”. If you are having these errors, you are at the right place. We will discuss it with some methods.

 

If Cached mode is turned on in your Microsoft Exchange server, it creates a replica of mailboxes and stores it in the system with .ost extension. Even if network is gone with Exchange Server, we can keep working with mails. There are various issues related to OST file corruption which could face ‘File is in use and cannot be accessed error.

Here are some of the main causes of error –

  • Some conflicts happened in MS Outlook.
  • Synchronization error between Exchange Server and OST
  • Accessing same OST by several users.
  • Slow connection and unreliable connectivity
  • Unauthorized access to OST file
  • Outlook process like LYNC, Office Communicator 2005/2007 running in background

Here are some of the methods to resolve the error “OST in Use and Cannot be accessed”

After detecting the error and knowing the reasons behind the same, this error can be fixed in next step. Here are some of the methods to help you know how to fix this OST error.

 

Close all Outlook based Processes

One of the best steps which can help you fix the errors related to inaccessible files is stopping the background process of MS Outlook. Here are the steps to do the task –

  • Close the MS Outlook properly.
  • Go to Task Manager by right clicking on Taskbar.
  • Choose the tab ‘Processes’
  • Search ‘Communicator’, ‘Lync’, ‘ucmapi’, or ‘Outlook’
  • If you choose any of them, choose process and click the button ‘End Task’.

 

Method 2 – Disable Cached Exchange Mode

You simply have to disable cached Exchange Mode with the following process in this method –

  • Open ‘Control Panel’ after selecting Outlook and choose ‘Mail’
  • Choose Email tab by clicking Email Accounts button
  • Click on ‘Change’ by choosing Email ID
  • Unselect Use Cached Exchange Mode > Next > Finish

 

Method 3 – Disable Outlook Add-ins

Add-ins are used to improve overall functionality of an application, whether it is Outlook or anything. A lot of faulty add-ins can make your application working weirdly. So, we need to disable such add-ins which can harm your Outlook or its files. Simply start Outlook in safe mode to disable those add-ins. Type Outlook/safe in Run command box in Windows. Click “Yes” if it asks “Do you want to start application in Safe Mode?”

 

Method 4 – Run Scanost.exe

This method is usually preferred to fix ‘OST file is in use. The file cannot be accessed” error to make OST file readable.

  • First of all, open Scanost.exe
  • Go to Mailbox>Select Repair Errors>Begin Scan
  • It will take few minutes to scan and fix the error in Repair process.

Be sure to use this method if you have Outlook 2007.

 

Method 5 – Using Professional Software

It is one of the most user-friendly, safe and recommended methods. You can quickly repair corrupt OST file with a professional tool. You can simply download OST Recovery Tool which is result-oriented and reliable tool. It can recover all your data from damaged or corrupt OST file. You can also save the data after recovery in another format like DBX, PST, EML, MBOX, and MSG.

Conclusion

You can easily use of these methods explained in this article after detecting the error with the cause. You need to fix the error ‘File Username.ost is in use and is inaccessible to keep working with emails. OST Recovery tool is the best choice for better and quick solution for OST to PST Conversion and to Open Corrupt OST file.

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