Software & Apps Windows How to Fix Mfc90u.dll Not Found or Missing Errors A Troubleshooting Guide for Mfc90u.dll Errors by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on February 20, 2020 Windows The Ultimate Laptop Buying Guide Tweet Share Email Mfc90u.dll errors are caused by situations that lead to the removal or corruption of the mfc90u DLL file, a file that's part of the MS Visual C++ runtime library. In some cases, mfc90u.dll errors could indicate a registry problem, a virus or malware issue, or even a hardware failure. The mfc90u.dll error message could apply to any program or system that might utilize the file on any of Microsoft's operating systems including Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, and Windows 2000. Mfc90u.dll Errors There are several different ways that mfc90u.dll errors can show up on your computer. Here are some of the more common ways that you might see mfc90u.dll errors: Mfc90u.dll Not FoundThis application failed to start because mfc90u.dll was not found. Re-installing the application may fix this problem.The ordinal 7426 could not be located in the dynamic link library mfc90u.dllCannot find [PATH]\mfc90u.dllThe file mfc90u.dll is missing.Cannot start [APPLICATION]. A required component is missing: mfc90u.dll. Please install [APPLICATION] again. Mfc90u.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 when the mfc90u.dll error occurs is a very important part of the troubleshooting process that will help narrow down which steps you need to take to fix the DLL error. How to Fix Mfc90u.dll Errors Do not download mfc90u.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 mfc90u.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 mfc90u.dll error. Download the Microsoft Visual C++ 2008 Service Pack 1 Redistributable Package MFC Security Update and run it. This will replace/restore the mfc90u.dll with the most recent copy provided by Microsoft. You're given a few different 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. Try your best to complete this step. Applying this update is almost always the solution to mfc90u.dll errors. Run the sfc /scannow System File Checker command to replace a missing or corrupt copy of the mfc90u.dll file. This DLL file is provided by Microsoft in some versions of Windows, so the System File Checker tool should restore it. Restore mfc90u.dll from the Recycle Bin. The easiest possible cause of a "missing" mfc90u.dll file is that you've mistakenly deleted it. If you suspect that you've accidentally deleted mfc90u.dll but you've already emptied the Recycle Bin, you may be able to recover mfc90u.dll with a free file recovery program. Recovering a deleted copy of mfc90u.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. Reinstall the program that's producing the mfc90u.dll error. If the mfc90u.dll error occurs when you use a particular program, reinstalling that program might help. 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 mfc90u.dll file could be included in one of those updates. Run a virus/malware scan of your entire system. Some mfc90u.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 mfc90u.dll error you're seeing is related to a hostile program that's masquerading as the file. Use System Restore to undo recent system changes. If you suspect that the mfc90u.dll error was caused by a change made to an important file or configuration, a System Restore could solve the problem. Test your memory and then test your hard drive. We'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 mfc90u.dll errors as they fail. If the hardware fails any of your tests, replace the memory or replace the hard drive as soon as possible. Repair your installation of Windows. If the individual mfc90u.dll file troubleshooting advice above is unsuccessful, performing a startup repair or repair installation should restore all Windows DLL files to their working versions. 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 mfc90u.dll error, this should be your next course of action. 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 mfc90u.dll error using a troubleshooting step prior to this one. Troubleshoot for a hardware problem if any mfc90u.dll errors persist. After a clean install of Windows, your DLL problem can only be hardware related. Need More Help? If you don't want to fix this DLL 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.