If your computer is freezing, crashing, or just acting strangely, you might think you need to download a heavy third-party diagnostic tool to figure out what's wrong.

You don't.

Windows has a hidden, built-in diagnostic tool called the Reliability Monitor. It taps into your system's internal logs and turns them into a clean, visual timeline. It shows you exactly when your PC crashed, which app caused it, and even when Windows installed a bad update.

Here is exactly how to access it in under 10 seconds.

Step 1: Open Command Prompt

  1. Press the Windows Key.
  2. Type cmd.
  3. Click on Command Prompt.

Step 2: Run the Reliability Command

Once the black terminal window is open, type this exact command and press Enter:

text

perfmon /rel

Step 3: Read the Timeline

A new window called Reliability Monitor will open. You will see a graph with a series of icons on a timeline. Here is what the icons mean:

  • Red 'X': A critical event (an app crash, Windows crash, or unexpected shutdown).
  • Yellow Triangle: A warning (an app failed to update, or a driver issue).
  • Blue 'i': Information (a successful Windows update or software installation).

If you see a lot of Red X's on a specific day, that tells you exactly when your PC started having problems.

Step 4: Find the Culprit

Click on any Red X or Yellow Triangle on the timeline.

Look at the bottom section of the window. It will list the exact Action and Details.

For example, if your browser keeps crashing, you will see Google Chrome listed as the source, along with an error code.

You can even click on "Check for solutions to all problems" at the bottom to have Windows try to fix it automatically.

Why this works

Most people rely on the "Event Viewer" to check for PC errors, but the Event Viewer is incredibly confusing and full of technical jargon. The Reliability Monitor uses the same data, but it translates it into plain English and organizes it by date. It is completely safe, works entirely offline, and is built right into your operating system.

If your PC is acting up, open this tool first. It will save you hours of guessing and prevent you from downloading fake "PC cleaner" software.