Error code

Windows 0x80070021

WINDOWS0x80070021
System Error Code· A POSIX/system errno returned when a system call fails.

What it means

The process cannot access the file because another process has locked a portion of the file..

How to fix it

  1. Close the application that has the file open.
  2. perform a clean boot and retry.
  3. reboot to release the lock.
  4. identify the locking process with Process Explorer.

Not affiliated with Windows. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.