Dealing With Logonui.exe Application Error

What is Logonui.exe?

The logonui.exe file refers to the Microsoft Logon User Interface, which is a process related to the Windows XP user switching screen. The file is extremely important for the stability of the system as it is required for several essential applications. The user is advised not to disable the process even if it is causing errors.

Some Facts About Logonui.exe:

  • Type of File: Application
  • System Process: Yes
  • Description: Windows Logon UI
  • Size: Approx 502 KB
  • Default Location: C:\WINDOWS\system32
  • Company: Microsoft Corporation
  • Security Level: Safe

What is a Common Logonui Executable Error Encountered on a System?

One of the common errors related to logonui is:

  • Logonui.exe- Application Error.

(With following details in error message window)

"The instruction at "0x7c9e868e" referenced memory at "0x00008023"; the memory could not be written”

It is necessary to fix the logonui executable error as it can cause instability in the system and also lead to several problems such as:

  • Faults during program installation and uninstallation
  • Frequent system restart
  • Corrupted registry entries
  • Blue screen of death
  • High or overloaded CPU usage

Can Logonui.exe be a Virus or Malware?

There is a possibility that a virus has created a dubious file with the same name to avoid detection. The best way to identify the genuine nature of an executable file is by checking the file properties. You can use the information given in the, “Some facts about logonui.exe file”, section of this article. If a file with the same name also resides in another location besides the default location, then there is a high probability of the file being a virus or a Trojan.

How to Fix the Logonui.exe Error

There are different ways of fixing the error related to the logonui executable file. Let’s take a look at a couple solutions and the steps involved in them:

Solution 1: Steps to resolve the error:

  1. Insert a Windows XP CD
  2. Boot from the CD-ROM
    (Note: You will be shown different options to restore your Windows)
  3. Select R
  4. Enter the administrator password and press Enter.
  5. Type the following: “copy userinit.exe wsaupdater.exe”
  6. Reboot your system
  7. Click on Start -> Run
  8. Type regedit
  9. Locate the userinit key in the registry at the following location-

  11. Make a modification to the entry C:\WINDOWS\System32\wsaupdater.exe to:


(Note: If you use Win NT you will find the entry C:\WINDOWS\System32\wsaupdater.exe under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\Current Version)

Solution 2: Steps to resolve the error:

  1. Insert the XP Setup CD in your CD/DVD drive
  2. Click on Start-> Run
  3. Type “expand D:\i386\logonui.ex_ %windir%\system32\logonui.exe”

(Note: D refers to the drive letter of the CD/DVD drive. Replace the drive letter as per your system specification)

The command replaces the corrupted logonui executable with the original copy of the logonui executable.

Users who are not comfortable performing the above mentioned task can use a good registry cleaner and scan for errors and fix the same. Using a registry cleaner is the safest way to get rid of errors due to corrupted registry entries.