Fix: a file cannot be accessed because it is locked by another program
Symptom
You see an error message similar to this:
MiKTeX cannot access the file '{path}' because it is either locked by another MiKTeX program or by the operating system.
How to fix
Some TeX editors are configured to run MiKTeX programs like pdflatex
in parallel. Use another TeX editor and see if this fixes the issue.