Process Explorer course

Handles and DLLs

Find who has a file open and which modules are loaded.

Enable the lower pane (View → Lower Pane View). DLLs shows modules in the selected process. Handles shows open files, keys, and other objects. The Find Handle toolbar search is the usual fix for “delete failed, file in use.”

If a handle search points at Explorer or a backup agent, close that path instead of rebooting. Reboot works and teaches you nothing.