How to Fix Authui.dll Not Found or Missing Errors

A Troubleshooting Guide for Authui.dll Errors

Screenshot of an authui DLL error message in Windows
Authui.dll Error Message.

Authui.dll errors are caused by situations that lead to the removal or corruption of the authui DLL file.

In some cases, authui.dll errors could indicate a registry problem, a malware issue like a virus infection, or even a hardware failure.

There are several ways that authui.dll error messages might be phrased depending on the cause of the problem. Here are some common authui.dll errors:

Authui.dll Not Found
The file authui.dll is missing.
This application failed to start because authui.dll was not found. Re-installing the application may fix this problem.
Cannot find [PATH]\authui.dll
Cannot start [APPLICATION]. A required component is missing: authui.dll. Please install [APPLICATION] again.

Authui.dll error messages might appear while using or installing certain programs, when Windows starts or shuts down, or maybe even during a Windows installation.

Noting at what point your authui.dll error shows up is an important piece of information that will be helpful during troubleshooting.

The authui.dll error message could apply to any program or system that might utilize the file on any of Microsoft's operating systems including Windows 10Windows 8Windows 7Windows VistaWindows XP, and Windows 2000.

How to Fix Authui.dll Errors

Do not download authui.dll from one of those DLL download sites. There are many reasons why downloading a DLL file is a bad idea. If you need a copy of authui.dll, it's best to obtain it from its original, legitimate source.

Start Windows in Safe Mode to complete any of the following steps if you're unable to access Windows normally due to the authui.dll error.

Recovering a deleted copy of authui.dll with a file recovery program is a smart idea only if you're confident you've deleted the file yourself and that it was working properly before you did that.

This is the most likely solution to a missing or not found authui.dll error. Please make every effort you can to complete this step after making sure your computer isn't infected with malware.

  • Use System Restore to undo recent system changes. If you suspect that the authui.dll error was caused by a change made to an important file or configuration, and System File Checker didn't help, a System Restore should solve the problem.
  • Reinstall the program that uses the authui.dll file. If the authui.dll DLL error occurs when you use a particular program, reinstalling the program should replace the file.
    • This step is most useful for replacing DLL files that are not supplied by Microsoft but it could help with your authui.dll problem if this program also provides a copy of the file and the previous troubleshooting ideas weren't successful.
  • Update the drivers for hardware devices that might be related to authui.dll. If, for example, you're receiving a "The file authui.dll is missing" error when you play a 3D video game, try updating the drivers for your video card.

The authui.dll file may or may not be related to video cards - this was just an example. The key here is to pay very close attention to the context of the error and troubleshoot accordingly.

We rarely recommend the use of registry cleaners. We've included the option here just in case it turns out to be helpful, in which case you could avoid the more difficult testing and last-resort options below.

To be clear, all the data on the drive you have Windows installed on will be deleted during a clean install so be sure to backup important files if you're able to. Obviously, make sure you've made every attempt possible to fix the authui.dll error using a troubleshooting step prior to this one before you take on a clean install.

  • Troubleshoot for an unknown hardware problem if any authui.dll errors persist.
    • A clean install of Windows is a fresh start on the software-side of the troubleshooting. So, unfortunately, if that didn't work, your DLL problem must be hardware related.

Need More Help?

If you're not interested in fixing this problem yourself, see How Do I Get My Computer Fixed? for a full list of your support options, plus help with everything along the way like figuring out repair costs, getting your files off, choosing a repair service, and a whole lot more.