How To Fix Mfc80u.dll Not Found or Missing Errors

A Troubleshooting Guide

Man working on laptop
Fixing Mfc80u.dll Error Messages. Hero Images / Getty Images

There are several different ways that mfc80u.dll errors can show up on your computer. Here are some of the more common ways that you might see mfc80u.dll errors:

  • "Mfc80u.dll Not Found"
  • "This application failed to start because mfc80u.dll was not found. Re-installing the application may fix this problem."
  • "Cannot find [PATH]\mfc80u.dll"
  • "The file mfc80u.dll is missing."
  • "Cannot start [APPLICATION]. A required component is missing: mfc80u.dll. Please install [APPLICATION] again."

Mfc80u.dll error messages might appear while using or installing certain programs when Windows starts or shuts down, or maybe even during a Windows installation.

The context of the mfc80u.dll error is an important piece of information that will be helpful while solving the problem.

Cause of Mfc80u.dll Errors

Mfc80u.dll errors are caused by situations that lead to the removal or corruption of the mfc80u DLL file.

In some cases, mfc80u.dll errors could indicate a registry problem, a virus or malware issue or even a hardware failure.

How To Fix Mfc80u.dll Errors

Do not download mfc80u.dll from a "DLL download" website. There are many reasons why downloading a DLL file is a bad idea. If you need a copy of mfc80u.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 mfc80u.dll error.

  1. Download the Microsoft Visual C++ 2005 Service Pack 1 Redistributable Package MFC Security Update and run it. This will replace/restore the mfc80u.dll with the most recent copy provided by Microsoft.
    1. You're given several download options from Microsoft for this update, based on the version of Windows you have installed - x86 (32-bit) or x64 (64-bit). See Am I Running a 32-bit or 64-bit Version of Windows? for help if you're not sure what to choose.
    2. Try your best to complete this step. Applying this update is almost always the solution to mfc80u.dll errors.
  2. Restore mfc80u.dll from the Recycle Bin. The easiest possible cause of a "missing" mfc80u.dll file is that you've mistakenly deleted it.
    1. If you suspect that you've accidentally deleted mfc80u.dll but you've already emptied the Recycle Bin, you may be able to recover mfc80u.dll with a free file recovery program.
    2. Recovering a deleted copy of mfc80u.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.
  3. Run a virus/malware scan of your entire system. Some mfc80u.dll errors could be related to a virus or other malware infection on your computer that has damaged the DLL file. It's even possible that the mfc80u.dll error you're seeing is related to a hostile program that's masquerading as the file.
  4. Use System Restore to undo recent system changes. If you suspect that the mfc80u.dll error was caused by a change made to an important file or configuration, a System Restore could solve the problem.
  5. Reinstall the program that's producing the mfc80u.dll error. If the mfc80u.dll error occurs when you use a particular program, reinstalling that program might help.
  6. Install any available Windows updates. Many service packs and other patches replace or update some of the hundreds of Microsoft distributed DLL files on your computer. The mfc80u.dll file could be included in one of those updates.
  7. Test your memory and then test your hard drive. I've left the majority of hardware troubleshooting to the last step, but your computer's memory and hard drive are easy to test and are the most likely components that might cause mfc80u.dll errors as they fail.
    1. If the hardware fails any of your tests, replace the memory or replace the hard drive as soon as possible.
  8. Repair your installation of Windows. If the individual mfc80u.dll file troubleshooting advice above is unsuccessful, performing a startup repair or repair installation should restore all Windows DLL files to their working versions.
  9. Use a free registry cleaner to repair mfc80u.dll related issues in the registry. A free registry cleaner program may be able to help by removing invalid mfc80u.dll registry entries that might be causing the DLL error.
    1. We rarely recommend the use of registry cleaners. I've included the option here as a "last resort" attempt before the destructive step coming up next.
  10. Perform a clean installation of Windows. A clean install of Windows will erase everything from the hard drive and install a fresh copy of Windows. If none of the steps above correct the mfc80u.dll error, this should be your next course of action.
  11. Troubleshoot for a hardware problem if any mfc80u.dll errors persist. After a clean install of Windows, your DLL problem can only be hardware related.

All the information on your hard drive will be erased during a clean install. Make sure you've made the best attempt possible to fix the mfc80u.dll error using a troubleshooting step prior to performing a clean install.

What This Error Applies To

The mfc80u.dll error message could apply to any program or system that might utilize the file on any of Microsoft's operating systems including Windows 8, Windows 7, Windows Vista, Windows XP, and Windows 2000.