When making a backup of the Outlook directory (\Users\<user>\AppData\Local\Microsoft\Outlook\), once in a while I would get an error saying that file copy can't be done. Actual error message says:
"Error 0x80070021: The process cannot access the file because another process has locked a portion of the file."
Obviously, this is after making sure that Microsoft Outlook has been closed, and verified via Task Manager (Ctrl + Shift + Esc). Normally, I would just restart the laptop, and restart the backup. But there's a better way.
If you have a smartphone that syncs with Outlook, make sure you disconnect it from Outlook.
If you have any other applications that make use or sync with Outlook's calendar, contacts, etc., like Lync or Skype, make sure you close those programs. In my case, it was Cisco WebEx Connect.
