If you receive an “Access Denied” error message when doing a Lock & Open using the Desktop App, it may be a result of your Windows Recycle Bin having become corrupted.

To fix a corrupted recycle bin you can open a Command Prompt (Admin) and enter the following command:

rd /s /q C:\$Recycle.bin

• You will know you have the right command prompt if it opens in \Windows\system32
• Change the drive letter from C:\ as required for your system
• This will also EMPTY the recycle bin

This article from Microsoft goes into more detail.

This article describes how to do it without using a command prompt.