What is mslbui.dll?

Mslbui.dll is a Windows DLL file. DLL is the abbreviation for Dynamic Link Library. DLL files are needed by programs or web browser extensions, because they contain program code, data, and resources. The following information can help you determine if mslbui.dll is a Windows system file or if it belongs to an application that you can trust.

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Mslbui.dll file information

The process known as LangageBar Add In belongs to software Microsoft Windows Operating System by Microsoft (

Description: Mslbui.dll is not essential for Windows and will often cause problems. Mslbui.dll is located in the C:\Windows\System32 folder or sometimes in a subfolder of C:\Windows. Known file sizes on Windows 10/8/7/XP are 25,088 bytes (91% of all occurrences), 25,600 bytes, 22,528 bytes or 27,136 bytes. 
A .dll file (Dynamic Link Library) is a special type of Windows program containing functions that other programs can call. This .dll file can be injected to all running processes and can change or manipulate their behavior. The program has no visible window. The service has no detailed description. The file is not a Windows core file. Mslbui.dll is able to record keyboard inputs. The file is a Microsoft signed file. Therefore the technical security rating is 67% dangerous, however you should also read the user reviews.

Recommended: Identify mslbui.dll related errors

Important: Some malware camouflages itself as mslbui.dll. Therefore, you should check the mslbui.dll 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 freezes everything except to shut down
  d kerr  
My first encounter with mslbui.dll was immediately after I loaded Microsoft Office Pro.
definitely harmless.
At the start of my computer, Pest Patrol picks it up and indicates that it's a program that monitors keyboard strokes. PP asks how I'd like to handle it- but also adds that no known virus was found in that particular folder. It also advices that I should make sure it isn't harmful spyware before actually acting on anything.
It attempted to connect to the internet trough my browser! And see what Alfred said:"program that monitors keyboard strokes". It smells fishy to me. In my computer it's located in C:\Windows\System32
I had it recently and it generated Stack Error attacks. It was camouflged malware. Removed it with the Pro version of Security Task Manager (Highly recommended).
  Allan Barker -  
microsoft language(tool)bar user interface file. USED by the MS IME interface for multiple languages. Mine are English and Japanese. It allows typing in both langages.
  Tom Hart   (further information)

Summary: Average user rating of mslbui.dll: based on 5 votes with 7 user comments. One user thinks mslbui.dll is essential for Windows or an installed application. One user thinks it's probably harmless. One user thinks it's neither essential nor dangerous. 2 users think mslbui.dll is dangerous and recommend removing it. 2 users don't grade mslbui.dll ("not sure about it").

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Best practices for resolving mslbui issues

A clean and tidy computer is the key requirement for avoiding problems with mslbui. 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 repairing of your installation or, for Windows 8 and later versions, 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 mslbui.dll 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

mslbui.dll [all]