built-in feature that can help you understand why a computer has started crashing, freezing, or behaving unexpectedly.
Unlike Task Manager, which mainly shows what is happening right now, Reliability Monitor gives you a history of important system events. This makes it particularly useful when a problem happens occasionally and you cannot immediately identify the cause.
What Is Windows Reliability Monitor?
Reliability Monitor is a Windows diagnostic tool that records information about system problems over time.
It can show application crashes, Windows errors, hardware-related problems, failed updates, and other events that may affect system stability.
The useful part is its timeline. Instead of looking through a long technical log, you can see when problems started and whether they are becoming more frequent.
How to Open Reliability Monitor
You do not need to download anything.
Press Windows + R, type:
perfmon /rel
and press Enter.
Windows will open the Reliability Monitor window and display a timeline of system activity.
You can also search for Reliability Monitor from the Windows Start menu.
Understanding the Reliability Timeline
The main screen shows a timeline organized by days.
Windows assigns a reliability rating to each day based on recorded problems. You will also see different events underneath the timeline.
A day with several application crashes or system failures can help you identify when a particular problem began.
For example, if your computer worked normally last week but started crashing after installing a new application, Reliability Monitor may help you notice that connection.
Application Failures
One of the most useful sections is Application failures.
If a program repeatedly stops responding or crashes, Reliability Monitor can record those incidents.
This is especially helpful when an application closes unexpectedly but does not provide a useful error message.
You can select an event to see additional information about the problem and determine which application was involved.
Windows Failures and Errors
Reliability Monitor also records certain Windows-related failures.
These events can include problems with Windows components, unexpected shutdowns, and other system issues.
Not every warning means that something is seriously wrong. Windows can record minor events that have little effect on normal use.
The important thing is to look for patterns, especially problems that happen repeatedly.
Failed Updates Can Reveal Problems
Windows updates sometimes fail because of compatibility issues, corrupted files, insufficient storage, or other system conditions.
Reliability Monitor can help you see when update-related problems occurred.
If your computer started behaving differently around the same time that several updates failed, that information can be useful when troubleshooting.
Hardware Problems
Some hardware-related problems may also appear in Reliability Monitor.
For example, Windows can record certain events related to device failures or unexpected system shutdowns.
Reliability Monitor is not a complete hardware diagnostic tool, but its history can provide useful clues when investigating an unstable computer.
Why the History Is So Useful
The biggest advantage of Reliability Monitor is that it shows when problems happened.
Imagine your computer crashes once every few days. By the time you try to investigate the issue, everything may appear normal.
Reliability Monitor gives you a record of previous incidents, making it easier to compare the timing of crashes with software installations, updates, or other changes.
What You Should Do After Finding an Error
Finding an error does not automatically mean you have found the cause.
Start by checking whether the same problem appears multiple times.
If one application has crashed repeatedly, check whether it has an available update or whether the problem began after a recent change.
If Windows-related errors keep appearing, make a note of their dates and descriptions before making major changes to the system.
Avoid deleting system files or changing advanced settings simply because an error looks technical.
Reliability Monitor vs. Event Viewer
Windows also includes Event Viewer, which provides much more detailed system logs.
Event Viewer is powerful, but it can be overwhelming because it contains a large amount of technical information.
Reliability Monitor is much easier for everyday troubleshooting because it presents important events in a simpler timeline.
For many users, Reliability Monitor is a good place to start before moving to Event Viewer.
When Should You Use Reliability Monitor?
You should consider checking Reliability Monitor when:
- An application keeps crashing.
- Windows suddenly becomes unstable.
- Your PC unexpectedly restarts.
- A problem started after installing software.
- Windows updates repeatedly fail.
- You want to find out when a recurring problem began.
It is particularly useful when the problem is intermittent rather than something that happens every time you use the computer.
A Simple Troubleshooting Method
If your PC has recently become unstable, try this approach:
- Open Reliability Monitor.
- Look at the days when the problems occurred.
- Identify repeated application or Windows failures.
- Check whether the problems started after a recent change.
- Search for the specific application or error information.
- Update or repair the affected software when appropriate.
- Monitor the system for a few days to see whether the problem returns.
Final Thoughts
Reliability Monitor is one of those Windows features that can easily go unnoticed. It does not promise to fix every computer problem, but it can make troubleshooting much easier by showing a clear history of crashes, failures, and other important events.
The next time your Windows PC starts acting strangely, you do not necessarily need another third-party diagnostic application. Reliability Monitor is already built into Windows, and it may provide the clue you need to understand what changed.