Resolved Error "Outlook.ost is in use and cannot be accessed"

Most of the people prefer MS Outlook in the terms of API, integration across email,calendar, contacts, offline access and different ways to find the email. There are many users who are working with it and they know how to fix the problem. But there are some issues while using Outlook OST file and cannot be accessed due to an error, this might get trouble for the users if they are not aware of troubleshooting.

Outlook ost is in use and cannot be accessed

Reason Behind the Outlook OST File Error

In this part, mentioned reason of being inaccessible the OST file in MS Outlook even in used, they are:

  • Generated an issue to configure between OST files on the local machine and MS Exchange Server.
  • The slow speed of internet connection.
  • Try to access the same OST file at the same time by the multiple users.
  • Runtime confliction between the Outlook Application with another application.

After mentioning, the problem behind it of MS Outlook OST file is in use and cannot be accessed. In the next part are going to mention solution of this problem.

Solution to Fixed Problem

The system asks you to restart it, but this is not a solution for that. The problem can fix into two different ways. They are:

  1. Terminate All Outlook Related Programe
  2. Disable The Cache Exchange Mode

1. Terminate All Outlook Programe

  • Run the Task Manager either by right click on the Taskbar or press Ctrl+Alt+Delete.
  • Choose the ProcessesTab.
  • Search for anything named "communicator", "Lync", "ucmapi" or "Outlook". If you find it related to these, select it and click the End task button.

2. Disable The Cache Exchange Mode

  • Close MS Outlook.
  • Open the Control Panel and select Mail.
  • Select the Email Accounts button.
  • Select the Email tab.
  • Highlighted email address show you the caution about OST file and select Change.
  • Uncheck Use cached exchanged Mode.
  • Select the Next button and the Finish button.

Now attempt to run the MS Outlook again. Definitely, will grant you access it. After fixing Outlook ost file error, you will be able to save OST MailBox into PST file format using manual and third party solution.