Program to monitor file usage and access

Question

Can you recommend me a program on Windows that can:

1. List all the files accessed by a running application
2. List all the applications accessing a given file

A GUI would be nice but not compulsory, and I need a freeware software, or one with free options.

Answer 1

ProcessMonitor from Microsoft (used to be Sysinternal) can record real-time access to files (and more)

https://docs.microsoft.com/sysinternals/downloads/procmon

This is useful if you want to record which files an application has accessed over time, e.g. during startup.

ProcessExplorer (a task manager replacement) can show the currently open files for an application

https://docs.microsoft.com/sysinternals/downloads/process-explorer

Using the "Find handle" option it's possible to find the applications accessing a specific file.