How to use System Informer: monitor processes and find locked files

What System Informer is and who it suits

System Informer is described as a free, powerful, multi-purpose tool that helps you monitor system resources, debug software and detect malware. It is MIT licensed and written in C, and it is brought to you by Winsider Seminars & Solutions, Inc.

It is a detailed monitoring tool rather than a simple cleaner. It suits Windows users who want more detail than Task Manager provides, people trying to find which program is locking a file, and developers profiling or debugging software on Windows.

• Best for: Windows users who want more detail than Task Manager, people finding which program locks a file, developers debugging on Windows, and anyone wanting a portable tool with no installation.
• Not for: macOS or Linux users, since the README lists only Windows 10 or higher; people wanting a one-click cleaner; users who need a guaranteed malware scanner.

Check the requirements and get the app

The project's system requirements are Windows 10 or higher, in either 32-bit or 64-bit versions. The project's download page is linked from the official website at systeminformer.com.

If you want to build it yourself rather than use the prebuilt app, the README says to clone the repository. Building requires Visual Studio 2022 or later, and the README points to the build readme for help if you run into trouble.

Find resource-hungry and runaway processes

System Informer gives a detailed overview of system activity with highlighting, and it includes graphs and statistics to help you quickly track down resource hogs and runaway processes. Use these views when your computer feels slow and you want to know which program is responsible.

Compared with Task Manager, the graphs and per-process detail make it easier to spot which process is consuming CPU, memory, disk or network activity over time.

• Open the overview and look for highlighted rows.
• Check the graphs to see which process is consistently using resources.
• Note the process name before deciding whether to close or investigate it.

Find which program is locking a file

If you cannot edit or delete a file, System Informer can show which processes are using that file. This is one of its most common uses, and it is useful when Windows reports that a file is in use but does not say by what.

Once you identify the process holding the file, decide carefully whether to close it, since closing the wrong program can cause data loss.

• Search for or locate the file you cannot delete.
• Review the processes listed as using that file.
• Close the program only if you are sure it is safe to do so.

Check network connections and disk access

System Informer lets you see what programs have active network connections, and you can close them if necessary. It also provides real-time information on disk access.

Use these views to find programs that are talking to the network or reading and writing the disk unexpectedly. Closing a connection is a deliberate action, so confirm what the program does first.

Use it portably and manage settings

System Informer is small, portable and needs no installation, so it can run from a USB drive. If you want to keep its settings on the drive too, the README describes creating a blank file named SystemInformer.exe.settings.xml in the same directory as SystemInformer.exe.

On Windows Explorer, first make sure "Hide extensions for known file types" is unticked in Tools > Folder options > View. Then right-click in the folder, choose New > Text Document, and rename the file to SystemInformer.exe.settings.xml, deleting the .txt extension.

Report problems and get help

The README asks users to report problems or suggest features through the GitHub issue tracker at github.com/winsiderss/systeminformer/issues. For build problems, the build readme in the repository is the referenced resource.

The project also links to a Discord server and an X account for community contact, though the README does not describe what support those channels offer.