Resource Monitor: see which app is using your disk, network or a locked file — via Microsoft Learn

Commandlow riskWindows 11Windows 10

Resource Monitor goes deeper than Task Manager. It shows which process is reading or writing which file, which app talks to which network address, and, with the search box under CPU → Associated Handles, which program has a file locked.

Takes effect right away

The easy way

  1. Run the command, or press Win + R and type it.
  2. File won't delete because it's 'in use'? Go to the CPU tab → Associated Handles and type part of the file name into the search box.

Command

Run in a normal Command Prompt / Terminal window.

perfmon /res
perfmon /sys opens the classic Performance Monitor graphs instead.

Sources

Source reviewed
2026-11-02
Link checked
2026-11-02
Tested hands-on
Not by Oddbyte.Me

Oddbyte.Me hasn't tried this on every Windows build, so keep the undo handy.

resource monitorresmondisk usagenetworkfile in use

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