You may receive the error 'Cannot copy file (1920): The file cannot be accessed by the systemwhen attempting to copy files from the WindowsApps folder or from other Windows folders. Due to security, Windows prevents access to some files even with the use of Volume Shadow Copy service (VSS) and elevation. 

The only solution is to exclude the files and/or folders file from your backup file/folder selections. You can deselect the file from:

    Modify > Simple > 'Choose sub-directories and files' settings page

We recommend not copying the folder \Users\[username]\AppData\Local\Microsoft\WindowsApps\