Microsoft Outlook is a software application that helps users manage their email accounts and calendars. It uses a data file called an OST (Offline Storage Table) to store information when an Exchange account is used. This allows users to access their accounts even when they’re not online. However, some users may encounter an error that says “The file username Ost is in use and cannot be accessed” when they try to launch Outlook. If you’re facing this problem, there are a few things you can try to fix it.
What causes the file username Ost to be in use and cannot be accessed errors in Outlook?
If you’re facing the “Outlook file username. Ost is in use and cannot be accessed” issue, there may be several reasons behind this error. Below we have given some reasons. The username. ost file is in use by another process
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- It occurs if the. Ost is still used or locked by the other process.
- It can happen from a conflict between the Outlook application and other files.
- It can happen, If the process Communicator, ucmapi.exe, etc. are running in the background.
- This error can also occur due to a lack of synchronization between the OST file and the Exchange mailbox.
Outlook, the file username Ost is in use and cannot be accessed
If you’re getting the “The file username. ost is in use and cannot be accessed” error message while logging into Outlook, then here are some methods to fix it: If you see the “The file username. ost is in use and cannot be accessed” error message while logging into Outlook, then here are some methods to fix it:
- Restart your system and router
- Disable Cached Exchange Mode
- End All the Outlook-related task
- Repair OST file with Inbox Repair Tools
Let’s use this method one by one to fix this error.
Disable Cached Exchange Mode
If you’re still seeing the same error after restarting your system, you may need to Disable Cached Exchange Mode to fix the issue. This will help users to work offline in Outlook. Follow the steps below to disable this option.
- First Launch the Outlook application and click on the File option in the upper left corner.
- Then Choose Account Settings and click on Account Settings.
- Go to the Email tab and select your account.
- Click on the Change tab.
- And now, you will see Offline Settings.
- Uncheck the box for the option Use Cached Exchange Mode.
- Restart the Outlook application to save the change.
Note: Don’t forget to turn “Use Cached Exchange Mode” ON if this error is not fixed.
End MS Outlook and related application
Close or end MS Outlook and related applications to fix the “Too many devices syncing” error, you’ll need to close or end any Outlook applications that might be running in the background. Make sure no Outlook application is running, then follow the steps below.
- Navigates to the Windows search bar, type Task Manager, and open it.
- Now Go to the Process tab.
- Look for the name Communicator, Outlook, Teams/Lync, or UCMAPI.
- If you get any options related to the application mentioned here.
- Then, select them and then click on the End task button in the bottom right.
- Now, restart your system to save the change.
Repair OST file with Inbox Repair Tools
When the methods above do not fix the issue related to the OST file, the file may be corrupted. In this case, you need to repair the OST file with Inbox Repair Tools. Microsoft has provided Inbox Repair Tool to recover folders and items from an offline folder. Ost file. It also helps recover items from corrupted personal folders or . Pst files.
How do I convert an OST to a PST file in Outlook?
To convert an Outlook OST file to a PST file, follow the steps below:
- First, open Outlook and click on the File in the top left corner.
- After that, click on the Open Export and select the Import/Export option.
- Now select the Export to a file option on the Import and Export Wizard Window page and click Next.
- Now select the Outlook Data File (.pst) and again click Next.
- Now, choose whether to export a specific folder or the whole account and also check the include subfolder box > click Next.
- Choose the destination for the Export by clicking on browse, and then click Finish.
Hello, My name is Shari & I am a writer for the ‘Outlook AppIns’ blog. I’m a CSIT graduate & I’ve been working in the IT industry for 3 years.