The MS Outlook application faces a few issues like an approaching mail getting affected by a virus, accidental deletion of items, hardware failure, and so on. However, a few errors happen because of not maintaining the Outlook application properly for the client, and you will find them very irritating because there are no committed techniques to evacuate them. You have to use different strategies and see which one expels the error.

One such error is the default Outlook profile.ost must be restarted. Here is its full content.

Default Outlook profile.ost error message

The error is engaging and shows that since you didn’t close the Outlook appropriately last time, you have to begin it indeed. You may confront a few performance issues with Outlook and see an extraordinary symbol, which shows that it is working at the issue.

Here are other few possible reasons for this error.

People Also

People Also Find Helpful: How to Change Profile Picture in Microsoft Office 365 (End-User & Administrator Methods)

Reasons Behind Default Outlook Profile.ost Must be Restarted  Error  

  1. The OST file is being used with another program. For instance, a client is using Office and Lync, and Lync has a handle on the OST file. Then again, Lync is used by Outlook as Add-in, for instance, the procedure ‘ucmapi64.exe’ is using the OST file, in this way it results in the Outlook error. 
  2. Introducing explicit Windows update. The error might be caused because of a specific Windows update. A couple of clients revealed the inappropriate conclusions of the Outlook profile subsequent to installing KB 3020338 on the Windows machine. The error is featured on this link.
  3. Windows machines are not upgraded. Windows admins may neglect to upgrade their machines, particularly the ones located on the system and this also causes this error.

Now, in order to fix the default Outlook profile.ost must be restarted error   here are some solutions:

Download Now Purchase Now

Also Read: 5 Ways to Resolve Outlook Stuck at Loading Profile Screen Error

Manual Methods to Fix Default Outlook Profile.ost Must be Restarted Error  

All the listed methods are verified and secure to use.

Solution 1: Restart the application and the system 

The easiest strategy is to reboot the email client or Microsoft Outlook and restart the framework. Sometimes, the email client may not react appropriately when it is shut without giving sufficient time for the Data files closure.

Solution 2: End the process related to Outlook

End the procedure connected to the Microsoft Outlook profile. For instance, the End process of Lync at the backend. To do so, follow these steps:

  1. Download and run Process Explorer. The procedure Explorer comprises two sub-windows – the top window shows active processes and the base window shows either the handles or the DLL, according to the procedure chosen from the top window.
  2. Go to the Find menu and search for “Find Handle or DLL“
  3. Look for ‘OST’. This will list every single open handle joined with the MS Outlook data file.
  4. Select and close all handles to the OST file.
  5. Run MS Outlook.

This may resolve the error, yet this a not a permanent solution.

Solution 3: Delete and Recreate Outlook Profile

Delete and recreate a new Outlook profile and modify the Outlook data file.

  1. From the Control Panel, find Mail and select Data Files from the Mail Setup – Outlook.
  2. On the Account Settings page, you will get to find the .ost file extension.
  3. Delete the OST file and run MS Outlook. It will rebuild the new OST file.

Solution 4: Uninstall the Windows Update

In the event that the error message is shown because of KB 3020338, at that point uninstall this Windows update with the assistance of the Windows admin and start Outlook.

Solution 5: Professional Solution to Fix The Error

The best and easy solution to fix the “default Outlook profile must be restarted” error is to convert the OST file to PST and then import it to MS Outlook using the Import/Export wizard.

The best and ideal approach is by using SysTools OST File Converter. This tool is best used by many organizations and users. However, it is easy to use as its interface is very simple and anyone can easily use this tool.

Download Tool Purchase Now

Follow the Below Steps to Use the Software

Step-1: Download, Install and Run the Software and Click on Add file button.

home window

Step-2: Browse the OST file from your computer. In case you don’t know the OST file location then the user can select the Search OST file option.

select file

Step-3: Preview the OST file items such as Emails, Contacts, Calendars, and other mailbox data items. 

change file

Step-4: Click on the Export button and Select the desired file format PST. After that browse the destination location to save the data. 

completed

Read: You can also understand the steps to import OST to Outlook. The user can also read another similar post Microsoft Outlook OST File Cannot be opened issue. 

Conclusion

In this blog, we have discussed the reasons for the error “default Outlook Profile.ost Must be Restarted Error” and also discussed the solution to fix this error. This error can cause by many reasons, so it is required to know the exact reason so as to use the ideal solution to fix the error.

Moreover, it is suggested to use manual methods under expert advice. Also, sometimes manual methods can cause data loss problems. So, if you are not handy with manual methods, then use an automated solution to resolve this issue. This issue can easily resolve by using OST to PST Conversion software without any data loss and error.

Also Read: OST File Not Recognized by Outlook 2007, 2010, 2013, 2016, 2019