What is slui.exe?

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the slui.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

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Slui.exe file information

Windows Task Manager with slui
Slui.exe process in Windows Task Manager

The process known as Windows Activation Client belongs to software Microsoft Windows Operating System by Microsoft (

Description: The original slui.exe is an important part of Windows and rarely causes problems. The slui.exe file is located in the C:\Windows\System32 folder. Known file sizes on Windows 8/7/XP are 325,632 bytes (66% of all occurrences), 349,184 bytes or 312,320 bytes. 
It is a Windows core system file. Slui.exe is a Microsoft signed file. Therefore the technical security rating is 11% dangerous, however you should also read the user reviews.

Recommended: Identify slui.exe related errors

Important: Some malware disguises itself as slui.exe, particularly when not located in the C:\Windows\System32 folder. Therefore, you should check the slui.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

It executes a window that allows the user to change the operating system key. It is run from the command prompt. The correct syntax in win 7 or 8 is "slui.exe 3"
The file is not needed for the operating system to work properly. It handles the legitimacy of the Windows licence and provides a nag and/or timed reboot if your version of Windows is not genuine.

Summary: Average user rating of slui.exe: based on 2 votes with 2 user comments. One user thinks slui.exe is essential for Windows or an installed application. One user thinks it's neither essential nor dangerous.

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Best practices for resolving slui issues

A clean and tidy computer is the key requirement for avoiding problems with slui. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off doing a repair of your installation, or in the case of Windows 8, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the slui.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

slui.exe [all]