mfc100kor.dll Is Missing: Fixes for Windows 10 and 11

mfc100kor.dll errors often appear as: “The program can’t start because mfc100kor.dll is missing from your computer. Try reinstalling the program to fix this problem.” mfc100kor.dll may also be reported as “was not found,” “could not be loaded,” or “not designed to run on Windows.”

The safest first fix is to repair or install the official Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update. Choose the package that matches the affected application: vcredist_x86.exe for a 32-bit program and vcredist_x64.exe for a 64-bit program.

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Which fix applies to you

Use the description that matches what you see:

• If several older programs fail with similar errors, install or repair both the x86 and x64 Visual C++ 2010 packages on 64-bit Windows.
• If only one application or game fails, repair or reinstall that program after installing the matching runtime.
• If the error appeared after an update, interrupted installation, or cleanup utility, rerun the official runtime installer and restart Windows.
• If the file is missing from a game folder, verify the game files through Steam, Epic Games Launcher, or the launcher that installed it.
• If Windows Security shows that the file was quarantined, inspect the detection before restoring anything.
• If the message says “not designed to run on Windows” or “contains an error,” suspect corruption, an incompatible architecture, or a damaged dependency.
• If the error names a program installed immediately before the problem began, that program is the best place to start.
• If multiple Windows features and applications are malfunctioning, run DISM followed by System File Checker.
• If the problem began directly after a system change, consider System Restore.
• If none of these steps works, collect the executable path, architecture, runtime entries, file details, and antivirus history before contacting the application vendor.

Do not begin by downloading a loose copy of mfc100kor.dll. A random DLL file may have the wrong architecture, an incompatible serviced version, malicious modifications, or missing dependencies. It may also be placed somewhere the application never searches.

What mfc100kor.dll actually is

mfc100kor.dll is a Korean-language MFC localization and resource DLL from the Microsoft Visual C++ 2010 family. MFC, or Microsoft Foundation Class Library, is a set of libraries used by applications built with Visual C++.

The kor suffix identifies Korean language resources. It does not mean that Windows must use Korean as its display language, and changing the Windows language normally does not repair this error. Korean is one of the supported MFC localization languages documented by Microsoft in TN057: Localization of MFC Components.

The file is commonly used alongside other VC10 runtime files, including:

• mfc100.dll
• mfc100u.dll
• msvcr100.dll
• msvcp100.dll

The exact file named in the error is not always the only file involved. Windows may report mfc100kor.dll because that is the first file a program requested, while the underlying failure is a missing dependency, an incompatible 32-bit or 64-bit file, or a damaged application installation.

mfc100kor.dll is not:

• A Windows-core DLL
• A DirectX component
• A .NET Framework component
• A graphics-driver file
• A normal COM or ActiveX control
• A file that should usually be registered with regsvr32

Microsoft describes localized MFC DLLs as redistributable components. They can be installed centrally by a Visual C++ redistributable package or deployed in the same folder as the application executable. The deployment model is explained in Microsoft’s MFC redistribution documentation.

Why the file can be in different folders

The location of the DLL can reveal which installation method the program uses.

On 64-bit Windows:

• C:\Windows\System32 contains native 64-bit system files.
• C:\Windows\SysWOW64 contains 32-bit system files.
• An application directory may contain a private copy supplied by the application vendor.

The names are confusing, but System32 is the normal location for 64-bit system files on 64-bit Windows, while SysWOW64 is used for 32-bit compatibility files. Windows applies file-system redirection based on the process architecture. Microsoft documents this behavior in its file-system redirector documentation.

A 32-bit program cannot load a 64-bit DLL. A 64-bit program cannot use a 32-bit DLL in place of its native dependency. The architecture of the application matters more than the architecture of Windows.

A centrally installed runtime may place files in Windows-managed runtime directories. An application-local installation may keep the files beside the program’s .exe file. Both arrangements are supported by Microsoft’s MFC deployment guidance.

Do not copy a file from System32 to SysWOW64, or the other way around, as a repair method. That can create a second problem without resolving the original dependency.

Fix 1: Install or repair the correct Visual C++ 2010 runtime

This is the most likely solution when the error affects more than one older application or when the missing file is expected to be centrally installed.

The official package is the Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update. Microsoft lists the package files as:

• vcredist_x86.exe for 32-bit applications
• vcredist_x64.exe for 64-bit applications
• vcredist_ia64.exe for Itanium systems

普通? No. Ordinary 64-bit Windows PCs use x64, not Itanium. Download the package from the official Microsoft Download Center. Microsoft also lists legacy Visual C++ packages in its supported Visual C++ Redistributable downloads.

Step 1: Check installed runtime entries

1. Press Windows + I.
2. Select Apps.
3. Select Installed apps.
4. In the search box, type Visual C++.
5. Look for entries containing Microsoft Visual C++ 2010 or Microsoft Visual C++ 2010 x86 Redistributable.
6. On Windows 10, open Settings > Apps > Apps & features if the newer Installed apps page is not available.
7. If you prefer Control Panel, press Windows + R, type appwiz.cpl, and press Enter.
8. Review both the x86 and x64 entries.

The existing entry may be present but damaged. Finding it does not prove that the runtime is working.

Step 2: Select the package architecture

Use the architecture of the program that fails:

Failing application	Package to install
32-bit application	vcredist_x86.exe
64-bit application	vcredist_x64.exe
Application architecture unknown on 64-bit Windows	Install both x86 and x64
Itanium system	vcredist_ia64.exe

Many Windows PCs need both x86 and x64 packages because a 64-bit operating system can run both kinds of applications. Installing only x64 does not satisfy a 32-bit program.

If you do not know the application architecture, install both x86 and x64 from the official Microsoft package page. This is generally the simplest approach when several programs are affected.

Step 3: Run the installer

1. Download the required package from Microsoft.
2. Open your browser’s download list or the folder where the installer was saved.
3. Right-click vcredist_x86.exe or vcredist_x64.exe.
4. Select Run as administrator.
5. Accept the license terms.
6. If the installer shows Repair, choose Repair.
7. If it shows Install, choose Install.
8. Wait for the installer to finish.
9. Restart Windows, even if the installer does not require it.
10. Start the affected application again.

If the installer reports that the package is already installed, use its Repair option if available. If repair is not offered, open Installed apps, select the Visual C++ entry, choose Modify, and select Repair when the maintenance dialog appears.

How to tell whether this worked

The fix worked if the application opens normally and no longer displays the mfc100kor.dll message.

If the same error returns, check the following before repeating the installation:

• You installed the architecture required by the application.
• You installed the Visual C++ 2010 package, not only Visual C++ 2015–2022.
• The error is coming from the program you repaired.
• Antivirus did not remove the file immediately after installation.
• The application does not require a private copy beside its own executable.

Installing the current Visual C++ 2015–2022 or v14 runtime does not necessarily replace Visual C++ 2010. Microsoft maintains older Visual C++ redistributables side by side, and the compatibility promise for later MSVC versions does not automatically cover older VC10 dependencies. Installing the current runtime alone is therefore not a reliable fix for mfc100kor.dll.

Microsoft’s legacy table documents Visual Studio 2010 SP1 runtime builds, while other Microsoft-serviced MFC packages document later builds. File size alone is not a reliable authenticity or compatibility test.

Fix 2: Repair or reinstall the affected application

If only one program fails, the application may have deployed mfc100kor.dll in its own installation folder. The file may have been deleted, corrupted, or separated from other VC10 dependencies.

Repair an installed Windows application

1. Press Windows + I.
2. Select Apps.
3. Select Installed apps.
4. Search for the affected program.
5. Select the three-dot menu beside it.
6. Select Advanced options if that option exists.
7. Select Repair.
8. Start the application again.

The Repair button is not available for every desktop application. If it is missing, use the application’s own installer or Control Panel.

For a classic desktop program:

1. Press Windows + R.
2. Type appwiz.cpl.
3. Press Enter.
4. Select the affected program.
5. Choose Change, Modify, or Repair.
6. Follow the installer prompts.
7. Restart Windows and test the program.

If repair does not restore the file, uninstall and reinstall the application from its trusted original installer. Save application settings or game saves first if the program stores them inside its installation directory.

Reinstalling the affected application is particularly important when the error identifies a DLL beside the program’s executable rather than a centrally installed runtime directory. The program’s installer may need to restore a specific MFC language resource file and its related dependencies together.

Fix 3: Verify game files through the launcher

An interrupted update can remove or corrupt a game’s private runtime files. Verify the installed files before downloading the entire game again.

Steam

1. Open Steam.
2. Select Library.
3. Right-click the affected game.
4. Select Properties.
5. Select Installed Files.
6. Select Verify integrity of game files.
7. Wait for Steam to complete the scan.
8. Start the game again.

Steam may replace missing or damaged files and may report that some files were reacquired. The exact behavior is controlled by Steam’s installation system. The official procedure is documented by Steam Support.

Epic Games Launcher

1. Open Epic Games Launcher.
2. Select Library.
3. Find the affected game.
4. Select the three dots beside the game.
5. Select Manage.
6. Select Verify.
7. Wait for the verification process to finish.
8. Start the game again.

Epic documents this process in its official game-file verification instructions.

If verification reports no problem but the game still cannot load, install or repair the matching Visual C++ 2010 package as well. The launcher may validate the game’s own files without repairing a system-wide runtime.

Fix 4: Check Windows Security quarantine

Antivirus software may remove a runtime DLL from an application folder. That does not automatically mean the detection is a false positive. The file could be genuine, modified, bundled with a compromised installer, or incorrectly detected.

Check the event before restoring anything:

1. Open the Start menu.
2. Type Windows Security.
3. Open Windows Security.
4. Select Virus & threat protection.
5. Select Protection history.
6. Open the detection related to mfc100kor.dll.
7. Record the detection name, file path, date, and originating application.
8. Check whether the file was in an official application directory or an unexpected location.
9. Do not choose Allow on device unless you trust the installer and understand the detection.
10. If the application is legitimate, uninstall or reinstall it from its official source instead of restoring an isolated DLL.
11. Run a new scan after reinstalling.

Microsoft explains how Protection History records detections and warns that restoring a quarantined item may cause Defender to detect it again. See Microsoft’s Protection History guidance.

If another antivirus product is installed, open that product’s quarantine or history page and perform the same checks. A trusted digital signature, a known installation path, and a clean official installer are more useful evidence than the filename alone.

If the file was quarantined from a game directory, verify the game files after resolving the security alert. If it was quarantined from a random download folder, do not restore it merely to remove the error.

Fix 5: Check for a missing dependency

A Windows loader message can name mfc100kor.dll even when another dependency is the real problem. The Korean resource DLL may be present, but mfc100.dll, mfc100u.dll, msvcr100.dll, or another required file may be missing or incompatible.

This is why replacing only the named DLL often fails.

Use this sequence:

1. Install or repair the complete Visual C++ 2010 runtime.
2. Repair or reinstall the affected application.
3. Verify game files if a launcher installed the program.
4. Check antivirus history.
5. Confirm the executable and runtime architectures match.
6. Restart Windows.
7. Test the application again.

Windows resolves DLLs using defined search rules that include the application directory and system locations. The full behavior is described in Microsoft’s DLL search-order documentation.

Do not add an arbitrary download folder to PATH to force Windows to find a DLL. Do not place a random copy beside the executable. Those changes can hide the underlying issue and introduce DLL-preloading risks.

Fix 6: Use Windows Features only for an application-specific requirement

Windows Features do not install the Visual C++ 2010 MFC runtime. Enabling random features will not normally repair mfc100kor.dll.

You can still check Windows Features if the application’s own documentation says it requires an optional Windows component:

1. Press Windows + R.
2. Type optionalfeatures.
3. Press Enter.
4. Review the available components.
5. If the application specifically requires .NET Framework 3.5, select it.
6. Select OK.
7. Allow Windows to download the required files if prompted.
8. Restart Windows if requested.
9. Test the application again.

Do not enable .NET Framework, legacy components, or compatibility features solely because the error names mfc100kor.dll. MFC localization files belong to the Visual C++ runtime family, not .NET.

Fix 7: Run DISM and System File Checker for broader Windows corruption

DISM and SFC are secondary fixes for this problem. mfc100kor.dll normally comes from Visual C++ or an application installer rather than from Windows’ protected core files, so SFC may not restore it.

Use these commands when several applications or Windows features are failing, when Windows Update is damaged, or when the runtime installer itself cannot operate correctly.

Run DISM

1. Open the Start menu.
2. Type Command Prompt.
3. Right-click Command Prompt.
4. Select Run as administrator.
5. Select Yes at the User Account Control prompt.
6. Enter:

DISM.exe /Online /Cleanup-Image /RestoreHealth

1. Press Enter.
2. Wait for the operation to complete.
3. Leave the Command Prompt window open.

DISM may take time and can appear to pause. Do not close it while it is working.

Run SFC

After DISM finishes successfully, enter:

sfc /scannow

Press Enter and wait until the verification reaches 100 percent.

Restart Windows after both commands finish, then repair or reinstall the Visual C++ runtime and retest the application.

Microsoft recommends running DISM before SFC in its System File Checker repair instructions.

Possible SFC results include:

• Windows found no integrity violations: protected Windows files were not identified as damaged.
• Windows found corrupt files and repaired them: restart and test again.
• Windows found corrupt files but could not repair some: repeat the runtime and application repair steps, then investigate the CBS log if necessary.

Running SFC repeatedly without changing the underlying runtime or application installation is unlikely to help when only one program fails.

Running DISM and SFC by hand can leave you hunting through results and guessing what changed; Outbyte PC Repair offers a free scan that shows exactly what is wrong, while repair is handled by the full version.

Fix 8: Install pending Windows updates

An interrupted installation or damaged Windows Installer state can prevent a runtime package from repairing correctly.

1. Press Windows + I.
2. Select Windows Update.
3. Select Check for updates.
4. Install available updates.
5. Restart Windows if requested.
6. Return to Windows Update and check again.
7. Rerun the official Visual C++ 2010 installer as administrator.
8. Test the affected application.

If Windows Update itself reports an error, record the error code rather than repeatedly clicking Check for updates. Microsoft provides current update installation guidance in its Windows Update instructions.

Windows updates do not replace the need for the correct VC10 package. This step is intended to repair the surrounding installation environment.

Fix 9: Check drivers only when the timing points to a driver change

A graphics-driver reinstall is not a direct fix for mfc100kor.dll. The DLL is an MFC localization resource, not a DirectX or graphics-driver component.

Driver troubleshooting is reasonable when the error began immediately after a driver update and other applications started failing at the same time.

Check Device Manager

1. Right-click the Start button.
2. Select Device Manager.
3. Expand Display adapters if the affected program is a game or graphics application.
4. Right-click the relevant device.
5. Select Properties.
6. Open the Driver tab.
7. Record the driver provider, date, and version.
8. Select Update Driver if an update is known to be required.
9. To undo a recent change, select Roll Back Driver if the button is available.
10. Restart Windows.
11. Test the application.

Do not uninstall a device as a first response to a missing MFC DLL. If you need to reinstall a driver, download it from the hardware manufacturer or the PC manufacturer, confirm the model, and create a restore point first.

Manually hunting through Device Manager means checking many hardware categories and driver versions one by one; Outbyte Driver Updater provides a free scan that shows exactly which drivers are reported as outdated, while driver installation is handled by the full version and remains optional when the real problem is an application-specific runtime.

If the application belongs to a game or vendor package, reinstalling that program remains the definitive fix for a missing private copy, regardless of driver status.

Fix 10: Use System Restore after a recent system change

System Restore is appropriate when the error started immediately after a cleanup utility, driver installation, application update, or other system change and the normal runtime repair did not help.

1. Press Windows + R.
2. Type:

rstrui.exe

1. Press Enter.
2. Select Next.
3. Choose a restore point created before the error began.
4. Select Scan for affected programs.
5. Review the applications and drivers that will be removed or restored.
6. Close any open programs.
7. Select Next.
8. Select Finish.
9. Confirm the operation.
10. Allow Windows to restart.

System Restore changes system files, registry settings, drivers, and installed programs. It does not normally remove personal files, but review the affected-program list carefully before confirming. Microsoft describes the process in its System Restore guidance.

After the restore completes, test the application. If it launches, avoid immediately reinstalling the same update or cleanup utility until you know what caused the failure.

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What the different error messages mean

“The program can’t start because mfc100kor.dll is missing”

This usually means the loader could not find the DLL in the locations searched for that application. Install or repair the matching Visual C++ 2010 package first.

If only one application fails, repair that application as well. The program may expect an application-local copy rather than a centrally installed runtime.

“mfc100kor.dll was not found”

This has the same practical starting point as the missing message, but it still does not prove that the named file itself is absent. A dependency or architecture mismatch can produce a similar result.

Install the complete runtime rather than copying only the named file.

“There was a problem starting mfc100kor.dll”

This can indicate corruption, an incompatible DLL, a missing dependency, or a failed application installation. Check the executable architecture, runtime architecture, antivirus history, and application files.

“The specified module could not be found”

This wording is often misunderstood. “Module” can refer to a dependency required by the named DLL, not only the named DLL itself.

Repair the complete runtime and the application. Do not assume that placing a copy of mfc100kor.dll in a random directory will fix it.

“mfc100kor.dll is either not designed to run on Windows or it contains an error”

This commonly points toward a bad image, corruption, architecture mismatch, or a file that does not belong to the application version. Record the full error and any status code shown.

Install the matching official runtime, repair the application, and inspect antivirus history. If the error persists, check the file’s digital signature and path.

These are commonly observed message variants, not a complete Microsoft error catalog. The exact status code and the executable named in the dialog are more useful than the wording alone.

Why regsvr32 is not the fix

Do not use regsvr32 to repair mfc100kor.dll.

regsvr32 is intended for self-registering COM, OLE, and ActiveX DLLs that expose a registration entry point. A runtime or resource DLL such as mfc100kor.dll is normally found and loaded by the application through the Windows loader. It is not normally installed through registry registration.

Running this command is not a repair:

regsvr32 mfc100kor.dll

It may produce an error stating that the entry point DllRegisterServer was not found, or that the module could not be loaded. That result does not mean the Visual C++ runtime is repaired.

Microsoft explains the intended use and common errors of the tool in its Regsvr32 guidance.

Why downloading a single DLL is unsafe

Searching for the filename and downloading the first matching result is risky for several reasons:

• The file may be malicious or tampered with.
• It may be the wrong architecture.
• It may belong to a different serviced build.
• It may not include the dependent VC10 files.
• It may be copied into a directory that Windows does not search for the affected process.
• It can conceal a damaged application installation.
• A manually placed DLL can create DLL-preloading or version-conflict problems.

Use the official Microsoft Visual C++ package or the installer supplied by the affected application. Microsoft explicitly supports application-local deployment of MFC localization files, but that does not mean an end user should download a loose file and copy it manually.

Manual deployment is appropriate when performed by the application vendor or a developer using an authentic Microsoft redistributable, the correct architecture, and the complete required runtime set.

If the file exists but the error remains

A visible file is not proof that Windows can load it.

Check these details:

1. Right-click the failing program’s shortcut.
2. Select Properties.
3. Open the Shortcut tab.
4. Note the Target path.
5. Open the folder containing the executable.
6. Check whether mfc100kor.dll is beside that executable.
7. Check whether related VC10 files are present.
8. Right-click the DLL and select Properties.
9. Open the Details tab and record the file version.
10. Open the Digital Signatures tab if it exists.
11. Confirm the signer and signature status.
12. Review Windows Security Protection History.
13. Confirm whether the program is 32-bit or 64-bit.
14. Install the matching Visual C++ package.
15. Repair the application.

You can often identify a 32-bit program by its installation path, but the path alone is not definitive. Program Files (x86) usually contains 32-bit applications, while Program Files commonly contains 64-bit applications on 64-bit Windows. Some vendors use custom directories, so confirm with the vendor or the program’s documentation when architecture is unclear.

Do not judge authenticity from file size alone. Microsoft documents multiple serviced builds of this MFC file, and a particular size does not prove that a copy is safe or compatible.

Information to collect if nothing works

Before contacting the application vendor, record:

• The complete error text
• Any numeric status code
• The full path of the affected executable
• The name of the application or game
• Whether the program came from Steam, Epic, Microsoft Office, or another installer
• Whether Windows is 32-bit or 64-bit
• Whether the application is 32-bit or 64-bit
• The installed Visual C++ 2010 x86 and x64 entries
• The location of mfc100kor.dll, if present
• The file version and size
• The digital-signature status
• Antivirus Protection History details
• Whether the issue began after an update, reinstall, cleanup, driver change, or quarantine event
• The result of application repair or launcher file verification
• The result of DISM and SFC, if you ran them

This information helps distinguish a missing central runtime from a private application copy, a dependency failure, a quarantine event, or an architecture mismatch.

Reinstalling Windows should be a last resort for one missing MFC runtime file. The usual resolution is to install the correct Visual C++ 2010 architecture, repair the application that requested it, or restore a quarantined file only after its provenance has been verified.

FAQ

Does kor mean I need Korean Windows?

No. The suffix identifies Korean MFC language resources. The application may load that resource regardless of the Windows display language.

Is mfc100kor.dll part of Windows?

No. It belongs to the Visual C++ 2010 MFC runtime family and may be installed by a redistributable package or bundled with an application.

Which Visual C++ package installs it?

Use the Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update. Choose vcredist_x86.exe for a 32-bit application and vcredist_x64.exe for a 64-bit application.

Will Visual C++ 2015–2022 fix the problem?

Not necessarily. Visual C++ runtime families remain side by side, and a newer v14 runtime does not automatically replace a VC10 dependency. Install or repair the Visual C++ 2010 package required by the application.

Should I install both x86 and x64?

On 64-bit Windows, installing both is reasonable when the program architecture is unknown or several programs are affected. A 32-bit program requires x86 even when Windows itself is 64-bit.

Can I copy the DLL from another computer?

Do not do this as a normal repair. The other computer may have a different architecture, serviced version, dependency set, or compromised file. Install the complete official runtime or repair the application.

Should I put the file in System32?

No. The correct location depends on the runtime installation and the application’s deployment model. Copying files into System32, SysWOW64, or an arbitrary folder can create architecture and search-order problems.

Should I run regsvr32 mfc100kor.dll?

No. regsvr32 is for self-registering COM and ActiveX-style DLLs. This MFC localization resource DLL is normally loaded by the application and does not normally require registry registration.

Will changing the Windows language fix it?

Usually not. The kor suffix identifies a language resource, but changing the display language does not reinstall a missing or damaged runtime file.

Should I run SFC first?

Usually not for this specific DLL. Repair the Visual C++ 2010 runtime and the affected application first. Run DISM followed by SFC when multiple Windows components are malfunctioning or the installer environment is damaged.

What if antivirus removed the file?

Inspect Protection History, record the detection and path, and reinstall the program or runtime from a trusted source. Do not automatically restore or allow the file.

What if the error started after a game update?

Use the game launcher’s file verification feature first. If that does not help, repair the Visual C++ 2010 runtime and reinstall the game’s prerequisites.

Is a graphics-driver reinstall necessary?

Not normally. mfc100kor.dll is an MFC localization runtime file, not a graphics-driver component. Consider driver troubleshooting only when a driver change coincided with broader failures.

Where should I get the file?

Get the complete Visual C++ 2010 redistributable from Microsoft or reinstall the application that supplied it. Avoid random DLL download sites and loose copies from unofficial sources.

Why does the error appear after reinstalling Windows?

A clean Windows installation may not include legacy Visual C++ 2010 components required by older software. Install the application’s prerequisites and the matching official VC++ 2010 package.

What is the definitive fix if only one program fails?

Repair or reinstall that program, preferably using its official installer or launcher verification process. The program may require a private copy of mfc100kor.dll beside its executable, which a system-wide runtime repair may not restore.

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