0x80070021 – Part of the file is locked

Another process has locked part of the file.

Stop using a drive with unusual noises, read errors or data loss. Do not format, initialise or repair speculatively; seek qualified recovery advice.

Close the file in all known programs and wait for ongoing copy or synchronization processes.
Save work and restart Windows. Then try the process again.
Ask other users if files are shared. Do not forcibly terminate unknown system processes.

Test after each step and stop when the issue is solved. Checkmarks are not permanently saved.