How to Fix Outlook Error Code ‍0x80070021?

Summary: The Outlook Error Code 0x80070021 blocks users from copying or backing up their PST files. This blog explains the causes and offers solutions to fix the error. It also introduces an advanced PST repair tool for extracting and saving mail items from inaccessible or corrupt PST files.

The Outlook error code 0x80070021 may occur when users try to copy, move, or back up their Outlook Personal Folders file (PST) from its default location to another location, such as a folder, drive volume, or external media. This error may appear in any Outlook version and prevent users from copying their PST files.

The accompanying error message states:

“An unexpected error is preventing you from copying the file. If you continue to experience this error, you can utilize the error code to seek assistance for this issue.

Error 0x80070021: Another process has locked a portion of the file, thereby denying access.”

Below we have discussed the various reasons and solutions to troubleshoot and address the Outlook error 0x80070021.

Reasons for Outlook Error Code 0x80070021

Three primary reasons may lead to Outlook error code 0x80070021 in Microsoft Outlook 2007, 2010, 2013, 2016, 2019, and 2021:

1. Locked PST File

The error code 0x80070021 may appear when the PST file that you are trying to copy or back up is locked or being used by Outlook itself, its processes, or another application.

2. Microsoft Outlook or Its Processes are Not Closed Properly

One possible reason for error 0x80070021 is that Outlook is not closed properly and still running in the background. This may happen due to improper application closure or exit. Obstacles, such as incompatible or faulty add-ins in the Outlook application, can hinder the smooth shutdown of the program.

3. Hardware or Software Related Issues

Sometimes problems with the storage media where the PST file is currently stored can lead to the error 0x80070021.

These include:

• Problems with the file system
• Storage media errors
• Bad sectors
• Issues with the Windows OS or other critical Windows services

Also Read: Outlook PST File Not Found: 3 Solutions

Solutions to Resolve Outlook Error Code 0x80070021

To troubleshoot and resolve the Microsoft Outlook error code 0x80070021, you can follow the following methods:

Method 1. Close Outlook and Its Processes

Follow these steps to close Outlook and related processes to fix the error 0x80070021

1. Close Outlook and press CTRL + ALT + DEL.
2. Click Task Manager > More details.
3. Find all Outlook processes.
4. Select and click the End Process button.
5. Then look for Lync and Skype for Business. Close these apps and processes.

• Begin by closing Outlook and accessing the Task Manager by pressing CTRL + ALT + DEL keys
• In the Task Manager window, select “More details” (skip this if the Task Manager is in expanded mode).

• Locate and identify all Outlook-related processes. You can click on the Name tab to sort the processes alphabetically and simplify the process.
• Select all the Outlook and related processes and click on the “End Process” button.
• Also, check and close any instances of Lync or Skype for Business if you find it in the Task Manager window. 
• Repeat the steps until you close all Outlook processes are terminated.

Furthermore, it is advisable to temporarily disable your antivirus tool, as it may be interfering with the copying or moving of the PST file.

2. Disable or Remove Faulty or Incompatible Add-Ins

To disable add-ins in Outlook, you can utilize Safe Mode by performing the following steps:

• Press the Windows key + R, type “Outlook.exe /safe” in the Run dialog box, and press Enter or click OK.
• Once Outlook opens in Safe Mode, navigate to the File tab, select Options, and choose Add-Ins.
• Click on the Go button.
• Uncheck all add-ins and click OK.
• Restart Outlook in its regular mode.

Now, attempt to copy or back up the PST file to your desired location and check if the issue is resolved.

3. Perform Clean Boot

Follow these steps to make changes and perform a clean boot:

• Press the Windows key + R keys, type “msconfig” and press Enter or click OK. 
• In System Configuration, click “Services“.
• Check “Hide all Microsoft services” and click Disable all.

• Click “Startup” and click “Open Task Manager.”
• In the Task Manager, click on the “Startup” tab.
• Select the items and “Disable.”

• Close the Task Manager.
• Go back and click on “Apply” and then “OK.”
• Restart system.

After the clean boot, the system will start with a minimal set of drivers and help resolve the error 0x80070021.

4. Uninstall MS Office Communicator App

Uninstall the MS Office Communicator app to resolve conflicts and fix error 0x80070021. The steps are as follows:

• Press the Windows key + R, type “appwiz.cpl” in the Run dialog box, and click OK.

• Locate and select the MS Office Communicator app (if it appears in the list).
• Click on the Uninstall button.
• Follow the on-screen instructions provided by the uninstallation wizard to complete the process.
• Restart your system.
• After the restart, try to copy your PST file.

Removing the obsolete MS Office Communicator app should help in resolving any conflicts and enable smooth copying or backup of your PST file within Outlook.

5. Restart Windows in Safe Mode

To copy and back up the PST file while avoiding error 0x80070021, you can attempt booting Windows in Safe Mode. Follow these steps:

• Press Windows + Power icon.
• While holding the Shift key, select Restart from the power options.

• After the restart, goto Troubleshoot > Advanced options > See more recovery options > Startup Settings.
• Click on the Restart button, which will present you with the Startup Settings menu.
• Press the key 4 to boot the system in Safe Mode.
• Log in to your system in Safe Mode and attempt to copy the PST file.
• Once the file is copied, restart the system normally to resume regular usage.

6. Use PST Repair Tool

If the previously mentioned solutions have not resolved the error code 0x80070021 or if you are still facing the issue, you can consider using a specialized Outlook PST repair tool, such as Stellar Repair for Outlook. This tool is specifically designed to effectively scan, recover, and save all mail items from a corrupt or damaged PST file to a new PST file while preserving the original folder structure.

With Stellar Repair for Outlook, you can effortlessly recover and save various mail items, such as emails, attachments, contacts, tasks, notes, calendar items, and more from inaccessible PST files to healthy Outlook-importable PST files.

Additionally, you have the option to export the recovered data directly to Office 365/Microsoft 365 or a live Exchange mailbox.

By utilizing this powerful tool, you can overcome the error code 0x80070021 and successfully retrieve, transfer, or copy your important data from problematic PST files.

Also Read: How to get Activation Key for Stellar Outlook Repair?

Conclusion

If you are encountering error code 0x80070021 while moving or copying your Outlook PST file from its current or default location to a different folder or drive, try closing all background apps and processes that may have access to the PST file.

If this doesn’t work, check the storage disk health and file system. If nothing works, the Outlook data file may be corrupt or damaged. By using an Outlook PST repair software such as Stellar Repair for Outlook, you can recover mail items from corrupt or damaged PST files and save them in a new Outlook-importable PST file at any location. Then copy this PST file or transfer it anywhere without experiencing the error 0x80070021.

Also Read: Stellar Outlook Toolkit- Why should you choose this 8-1 Tool?