What Is LSAISO.exe and How to Reduce Its High CPU Usage

Get your PC running normally again

When your PC suddenly slows down because of a random process, it can be easy to assume it’s malware – but occasionally, it’s because of a legitimate Windows program. LSALSO.exe is one such Windows process that often malfunctions, causing extremely high CPU usage.

In this article, we’ll explain what the LSALSO.exe process is, why it causes high CPU usage, and how to fix it.

What is LSALSO.exe?

LSALSO.exe (or LSA Isolated) is a legitimate Windows executable file that’s associated with Microsoft’s Credential Guard & KeyGuard process. It’s an essential process known as a “trustlet”. This is a secure process that helps the Windows operating system complete system calls.

LSALSO.exe exists in a secure environment called Virtual Secure Mode (VSM) as an Isolated User Mode (IUM) process. VSMs are a security feature introduced in Windows 10 that ensures that processes within different Virtual Trust Levels (VTLs) can’t access memory in other VTLs. Essentially, this prevents inappropriate access (protecting against malware and other security issues).

The Local Security Authority (LSASS) manages system policy, user authentication, and handles sensitive data like password hashes and Kerberos keys. The LSALSO.exe process ensures that the system can communicate between different VTLs. In short, LSALSO.exe runs in VTL1 and shares encrypted communication withLSASS.exein VTL0, preventing malicious code from running in VTL0.

Why Does LSALSO.exe Have High CPU Usage?

While LSALSO.exe is a secure and trusted Microsoft Windows process, it’s often associated with high CPU usage. This is usually caused when drivers or other applications try to load a Dynamic Link Library (DLL) file into LSALSO.exe. Occasionally during this process, the system destabilizes, causing increased system usage.

However, there are other potential causes of high CPU usage in LSALSO.exe, including,

How to Fix LSALSO.exe High CPU Usage

Here are 5 ways to fix the LSALSO.exe process when it’s causing high CPU usage:

The first step is to make sure whether the LSALSO.exe process is legitimate or not. To do so:

Either way, it’s a good idea to scan your PC for potential malware and viruses. Open your antivirus software and scan your PC. If you don’t have a third-party antivirus installed, you can use Windows Defender as follows:

Unfortunately, it isn’t possible to use the Windows Debugging Tools to check for the causes of LSAISO.exe CPU spiking. This means that you’ll have to use the process of elimination to remove applications and drivers that could be at fault.

The first step is to disable as many applications as possible until the LSALSO.exe file stops spiking. To do so:

If ending a certain task stops the LSALSO.exe from spiking, you know what you’re dealing with. It may be a one-off, in which case you won’t need to do anything. However, if it happens again (with the same process), you should update or uninstall that application to prevent future incidents.

If the LSALSO.exe task is still showing high CPU usage, it’s time to disable ormanually update your drivers.

To do so:

While you can’t use Windows’ debugging tools to find faulty applications, you can use them to determine whether a driver is at fault.

First, download and install theWindowsDebugger(WinDbg). If your version of Windows is prior to the Windows 10 Anniversary Update, you’ll need to installVisual Studioand download the right version of theWindows Driver Kit (WDK).

Next, you need to create a kernel memory dump during the CPU spike. This will help you determine which driver is at fault.

To do so:

If no driver is listed under LSALSO.exe, it means there are no queued APCs.

If the above methods didn’t help you resolve the high CPU usage issue, you could try resetting Windows to its factory defaults. Often, this fixes any residual issues with drivers and other applications and returns the LSALSO.exe process to its default state.

Check out our in-depth guides on how to factory resetWindows 10andWindows 11.

Reduce CPU Usage For Better Results

There’s nothing worse than having a random process chew up your system resources for no obvious reason. Hopefully, this troubleshooting guide has helped you resolve your issues with LSALSO.exe and get your PC running like normal once again.

Jake Harfield is an Australian freelance writer whose passion is finding out how different technologies work. He has written for several online publications, focusing on explaining what he has learned to help others with their tech problems. He’s an avid hiker and birder, and in his spare time you’ll find him in the Aussie bush listening to the birdsong.Read Jake’s Full Bio

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