• February 20, 2024

How to fix error 0x80070021 on Windows 7 and 10?

Some Windows users receive error 0x80070021 while trying to copy or move individual files to other directories. There are also those who see it fail when trying to manage the WCF ASP.NET service. And yet, in the vast majority of cases, the error is displayed after trying to open Outlook files with the pst and ost extensions.

Causes of Error 0x80070021

As a result of a long study and analysis of numerous user reports, it was possible to calculate the true causes of the problem.

Main sources of malfunction:

  • Disabled HTTP redirection. If an error occurs while trying to start a WCF service in pure ASP.NET, then the problem is most likely a disabled HTTP activation. To fix the problem that appears, run this component in Windows.
  • The suitable ASP.NET version is disabled. Most likely, some application is running a newer or older version of ASP.NET that is currently disabled on the computer. In such a scenario of the development of the problem, the solution will be to include a suitable version of this OS component.
  • Outlook files are already used by some program. Antiviruses, various editors, anti-spam filtering systems can keep Outlook files running even if the application is closed in a standard way. A hung element in the system will provoke a typical error with every attempt to open or edit. You need to close all programs that are using the file.
  • There is an e-mail indexer. A misconfigured Outlook called email indexer often triggers error 0x80070021. Quite a few users have already reported fixing the problem after deactivating the problem setting.
  • A conflict between MS Office Communicator (Lyns) and Office Communicator or its successor Lyns may not work correctly when paired with Outlook. They can protect the file from any changes.
  • Third-party processes are conflicting with the file that is causing the error. It is rather difficult to determine the presence of interference with the file from other programs. The best way is to boot the system into Safe Mode.

Having identified the potential causes of error 0x80070021, it is much easier to find a way out of this situation. This material will help, because the methods described below are aimed at combating the listed problems. To restore normal operation as quickly as possible, it is best to use the methods exactly in the order in which they are posted here. The first methods are usually more efficient and do not require much time. The latter methods are more difficult to implement, and the need for them arises less often.

Method 1: enable HTTP activation from .NET Framework 4.5 services

If a message with an error code appears while starting a WCF service in a pure ASP.NET application, most likely the matter is in the inactive “HTTP activation” option. It is rationally and in practice proven that including some of the .Net Framework 4.5 advanced services from Windows Components helps in fixing the problem. The method is tested and fully working in Windows 7 and 10.

Quick start guide:

  1. Press the key combination Win + R, after which the Run dialog box opens.
  2. In the line that appears, enter appwiz.cpl and press the Enter key, the “Programs and Features” window will open almost immediately.
  3. From the menu on the left, go directly to the section “Enabling and disabling Windows components”.
  4. Expand the directory with the actively used version of the .NET Framework, and select “WCF Services” from the drop-down list.
  5. In the inner section of the list, check the box next to “Activate via HTTP” and close the window with the “OK” button.
  6. Restart your computer and check if the problem is fixed.

If the method is not applicable to the present situation, or the error continues to appear even after performing the listed actions, it is worth moving on to the next method.

Method 2: enabling ASP.NET 4.5, 4.6, 4.7

The method is relevant for those who have Windows 8.1 or an older version of the system along with IIS 8.5 or newer. Registering an updated ASP 4.5, 4.6 or 4.7 component should help. Several users have already reported that the method worked for them in the system.


  1. Right-click on “Start” and select the “Programs and Features” option.
  2. From the vertical menu of the new window, open the section “Enabling and disabling Windows components”.
  3. Open the “Internet Information Services” section.
  4. Go to Internet Services and Application Development Components.
  5. Check the box next to the newest version of ASP.NET, in this case ASP.NET 4.6.
  6. Click on the “OK” button to save the changes and restart the system.

It’s time to check if the method worked or if you need to continue to follow the instructions.

Method 3: close Outlook from the “Task Manager”

It is recommended to resort to the method if error 0x80070021 manifested itself when trying to copy a file or data from it to another location, it can be a cloud, a flash drive, another logical or hard drive. You won’t be able to move because the file is backed up in Windows by Outlook. If it is open now, the program should be closed by clicking on the cross at the top of the window. Even after closing the program interface, it can continue to work. Outlook tends to keep running in the background. To regain full control of the file, the application must be closed.

Important! If you are using the Cloudmark DesktopOne spam filter, you should close it before starting the next procedure.

How to close Outlook completely:

  1. Click on the cross in the upper right corner of the application.
  2. Right-click on the “Taskbar” (the line at the bottom along the entire length of the screen) and select “Task Manager”.
  3. Click on the “Details” button to show all the processes in the system.
  4. Find the Microsoft Outlook process, select it and press the Del key.
  5. Try to move the file again.

It is worth remembering! Several processes from this program can be launched in the system at once. All of them should be closed sequentially, otherwise the method will not work.

Method 4: remove the email indexer

The COM add-in can also cause the problem because it prevents Outlook from closing completely by default. The application already tends to run in the background, and this add-on forces the utility to keep running even after it is closed. Attempting to edit or move a file causes a conflict and error 0x80070021.

Some users reported that they fixed the problem by disabling the Search Email Indexer add-on. However, not only this setting can prevent the complete shutdown of the utility, there may be others.

A basic guide to disabling add-ons:

  1. Open the Outlook utility.
  2. Click on the “File” button in the top panel and click on the “Options” option from the drop-down menu.
  3. In the Outlook settings, go to the “Add-ins” section, the link to which is located in the left pane of the window.
  4. Scroll down the list of add-ons and expand their full list using the button at the end of the page.
  5. Select COM add-ins and a list of currently active functions will open.
  6. Click once on the email indexer (or other add-on) and click on the “Delete” button.

Method 5: uninstall MS Office Communicator

Another application that can be causing the problem is Microsoft Office Communicator. Today it is used very rarely, but in many systems the program is still preserved. This is a client for creating a secure connection with a subscriber, supports both conversations and video calls. Microsoft has already dropped support for the application. The same is true for the receiver – MS Lync, this application can also cause problems.

This outdated utility can lead to conflicts with more current and new software products from the Office suite, in particular – Microsoft Outlook. There are already known cases when error 0x80070021 passes after removing the problematic application – Communicator.

Step-by-step instruction:

  1. Click RMB on “Start” and select “Programs and Features”.
  2. In the list of installed utilities that opens, you need to find Microsoft Office Communicator.
  3. Click on the RMB program and select “Delete”.
  4. Confirm deletion.
  5. Turn the computer off and on again, then check if the failure appears.

Method 6: Boot into Safe Mode

Windows in Safe Mode does not load all unnecessary programs, so the file will remain free from any applications. Almost 100% the user will be able to perform any operation with the Outlook file without encountering an error.

How to start Windows 10 in Safe Mode:

  1. Press Win + R, paste ms-settings: recovery and click on Enter.
  2. From the “Recovery” tab, go to the “Update and Security” page.
  3. Go to the “Recovery” tab from the vertical menu.
  4. Click on the “Restart Now” button from the “Special Boot Options” section.
  5. As soon as the computer restarts, the user gets into the “Advanced Startup Settings”, here you need to open the “Troubleshooting” section.
  6. Then open “Advanced Options” and click on “Launch Options”.
  7. After a reboot, a window opens with options for enabling, here you should click on the fourth option, it is responsible for enabling safe mode.
  8. Perform the desired action on the file that previously caused the error.
  9. Restart the computer again to return to normal operation.

Any of the listed methods will definitely help get rid of error 0x80070021 and allow you to get full access to Outlook files. Most likely, closing the conflicting applications and configuring ASP.NET will do whatever is necessary. Only as a last resort you will have to resort to safe mode.

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