How to Resolve Error 0x80070021 in MS Outlook

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  • Updated on September 6th, 2023

Summary: When users face Outlook error code 0x80070021, that leads to stop them from copying or backing up their Personal Folders file (PST) file from its default location to another folder, volume, or external drive. So here, we will explain the various solutions to resolve error 0x80070021. Moreover, we will also include an automated Outlook PST Repair Tool to repair the above error in just a few clicks. Download Now   Purchase Now

MS Outlook is a desktop-based email client facilitated by Microsoft Suite, which is worldwide popular for its features and capabilities. It is an excellent email client that allows users to send and receive emails and perform tasks, to-do lists, notes, journals, calendars, and so on. However, there is also a disadvantage of Outlook that it can occasionally experience errors, just like any other software application. Therefore, let’s move ahead to study the scenarios that lead to error 0x80070021 in Outlook.

What Causes Outlook Error 0x80070021?

There are many reasons for Outlook Error 0x80070021, so here we are describing some of them.

  1. If the Office program you have installed in your system is corrupted, you may encounter the error 0x80070021 or Microsoft Outlook Not Responding issue.
  2. When your Outlook data is being used by another system or program.
  3. Abnormal termination of the Outlook program while running the program is another major cause of this error.
  4. If you have a problem with your software, then it might prevent you from transferring or storing data from your PST file.

These are some common reasons that can generate 0x80070021 Outlook errors. So let’s move forward to learn the method that can help you to solve this issue.

Methods to Resolve Error 0x80070021

On the internet, you find many solutions, but here, we are providing you with the most relatable ways to fix error 0x80070021 in Outlook.

Method 1: Perform Clean Boot

  1. Press Windows+R and then type MSConfig in the Run dialog and click OK to continue.
  2. Choose Services, then check the option Hide all Microsoft services and click Disable all.
  3. Select Startup and click the Open Task Manager option.
  4. Here you can see the list of startup items and then Disable the unnecessary items.
  5. Click on the OK button and restart the application and check if it is working or not.

Method 2: Close Outlook Process with Task Manager

The other reason for this error is that Outlook might be running in the background even after it is closed. So, to fix the Outlook error 0x80070021, try to close Outlook.

  1. Right-click on the Windows taskbar and choose “Task Manager” from the context menu to continue.
  2. Scroll down for Outlook or any other program that uses features of Outlook, then right-click it to choose the End task.

By applying the above method, you will be able to resolve error 0x80070021 in MS Outlook. If you are still facing the same issue, you should move to the next solution.

Method 3: Remove the Search Email Indexer

It is another reason to face error 0x80070021 that the process cannot access the COM Add-in, which may prevent Outlook from closing completely. That means it forces Outlook to leave behind a background process even if the application is closed. Hence, uninstall the COM Add-in that can trigger the error code 0x80070021.

  1. Launch Outlook on your system.
  2. Go to File >> Options >> Add-ins.
  3. Scroll down and click on the Manage option and select COM Add-ins and click Go to see the list of installed Add-ins.
  4. Finally, choose the Search Email Indexer and click on it to remove it permanently.

Now open your Outlook and check whether the error 0x80070021 Windows 10 is solved.

Method 4: Resolve Error 0x80070021 Using Automated Tool

Outlook PST Repair Software is a proficient and reliable tool to repair corrupt and inaccessible PST files. This tool offers three different modes for scanning the PST files, such as Standard, Advanced, and Deep, to restore or repair Outlook and fix Common Outlook errors.

Step-by-Step Guide to Fix Outlook Error 0x80070021

  1. Download and Install the Outlook PST Repair Tool.
  2. Select the PST file and choose the recovery mode (Standard, Advanced, Deep).
  3. View the PST file details, scan it, and click the Ok button.
  4. Check the folders that you require to repair from the tree structure and then click Save.
  5. Assign a destination path to save the new file.
  6. Choose the saving formats and other in-built features from the software. Finally, click OK to fully repair your PST file.


In short, the above article explains the reasons and methods to resolve Error 0x80070021 in MS Outlook without losing any data. We have described several manual procedures that can fix this issue, But still, if you face this error in Outlook, then we suggest you use the professional solution, which is a one-stop solution for your requirement.

About The Author:

Suman Rawat is a technical content writer and expert in the fields of email migration, data recovery, and email backup. Her passion for helping people has led her to resolve many user queries related to data conversion and cloud backup.


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