mfc100enu.dll Won’t Load: Rebuild the VC++ 2010 Runtime

mfc100enu.dll is a Microsoft Visual C++ 2010 MFC localization component. When Windows reports that it is missing or cannot load, repair the complete Visual C++ 2010 SP1 runtime instead of downloading a loose DLL.

The most reliable repair is:

1. Install or repair the official Visual C++ 2010 SP1 Redistributable.
2. Install x86 for a 32-bit application and x64 for a 64-bit application.
3. On 64-bit Windows, install both packages if you are unsure which architecture the program uses.
4. Repair or reinstall the affected application if it carries its own runtime files.

What mfc100enu.dll is

mfc100enu.dll belongs to the Microsoft Foundation Class, or MFC, runtime used by applications built with Visual C++ 2010. The enu portion identifies English-language resources. Microsoft’s Visual C++ file tables place the file in the Microsoft.VC100.MFCLOC component for both x86 and x64 packages. The Microsoft security-update file table documents its inclusion in those packages.

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It is not a guaranteed base-Windows file. A program may receive it from:

• The Microsoft Visual C++ 2010 SP1 Redistributable.
• The installer for an older Windows application or game.
• An application-local runtime stored beside the program executable.
• Another Microsoft product that carries the same MFC runtime component.

Microsoft documents both central deployment and application-local deployment in its MFC redistribution guidance.

A missing-file message therefore does not automatically mean that Windows itself is damaged. It usually means that a program can no longer find the Visual C++ 2010 MFC files it was built to use.

Quick identification table

Item	Correct identification
File	mfc100enu.dll
Runtime generation	Visual C++ 2010, also called VC10
Component	MFC language-specific resources, English
Related files	mfc100.dll, mfc100u.dll, mfcm100.dll, mfcm100u.dll, msvcr100.dll, msvcp100.dll
Required package	Microsoft Visual C++ 2010 SP1 Redistributable
32-bit program	x86 redistributable
64-bit program	x64 redistributable
Unknown program on 64-bit Windows	Install both x86 and x64
Normal central locations	%windir%\System32 for x64, %windir%\SysWOW64 for x86 on 64-bit Windows
Application-local location	The folder containing the affected program’s .exe
Registration with regsvr32	Not required and not a supported repair method

The 100 in the related filenames refers to the Visual C++ 2010 runtime generation. It does not mean that the modern Visual C++ 2015–2026 package can replace it.

Error messages caused by this problem

The wording depends on the Windows version, application, loader, and language. Common forms include:

The program can’t start because mfc100enu.dll is missing from your computer. Try reinstalling the program to fix this problem.

This application has failed to start because mfc100enu.dll was not found. Re-installing the application may fix this problem.

The code execution cannot proceed because mfc100enu.dll was not found.

Error loading mfc100enu.dll. The specified module could not be found.

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mfc100enu.dll is either not designed to run on Windows or it contains an error.

You may instead see mfc100.dll, mfc100u.dll, msvcr100.dll, or msvcp100.dll named in the message. They belong to the same general Visual C++ 2010 runtime family.

The phrase “specified module could not be found” needs particular care. Windows may name mfc100enu.dll even when a dependency used by that DLL is the file that is actually missing. Replacing only the named file can therefore leave the application broken. Microsoft explains this behavior in its documentation for the DLL search order.

Fix 1: Install or repair Visual C++ 2010 SP1

This is the correct first repair for most mfc100enu.dll errors.

Microsoft’s official package is the Visual C++ 2010 SP1 Redistributable Package MFC Security Update. Use the official Microsoft Download Center page, which provides the x86 and x64 installers.

You can also use the direct Microsoft downloads:

• Download vcredist_x86.exe
• Download vcredist_x64.exe

Choose the correct architecture

A 64-bit Windows installation can run both 64-bit and 32-bit programs. Those programs use different runtime packages.

• A 32-bit program requires the x86 package.
• A 64-bit program requires the x64 package.
• A 64-bit Windows PC often needs both packages because it commonly runs programs of both types.

This is why installing only the x64 redistributable can fail to repair an older 32-bit game or utility. Microsoft describes the architecture-matching requirement in its Visual C++ redistributable guidance.

To check your Windows architecture:

1. Open Start.
2. Select Settings.
3. On Windows 11, open System > About.
4. On Windows 10, open System > About.
5. Read System type.

If it says 64-bit operating system, download and run both installers when the affected program’s architecture is unknown. If it says 32-bit operating system, run only the x86 installer.

The program’s architecture is not always obvious from its name. Older games, business software, printer utilities, and installers are frequently 32-bit even on a 64-bit PC.

Install the packages

1. Close the affected application.
2. Download the required installer or both installers from Microsoft.
3. Open your Downloads folder.
4. Double-click vcredist_x86.exe.
5. Accept the license terms.
6. Choose Install.
7. If the installer offers Repair, select it instead.
8. Wait for the operation to finish.
9. Repeat the process with vcredist_x64.exe on 64-bit Windows.
10. Restart Windows.
11. Start the affected program again.

Microsoft’s current legacy-runtime page lists the Visual C++ 2010 SP1 x86 and x64 redistributables separately. The package page may also show an IA64 download intended for obsolete Itanium systems. That package is not the normal choice for an Intel or AMD Windows PC.

Repair an existing installation

If the installer says that the package is already installed, repair it from Windows.

On Windows 11:

1. Open Start > Settings.
2. Select Apps > Installed apps.
3. Search for Visual C++ 2010.
4. Open the menu beside the x86 or x64 entry.
5. Choose the available Modify, Change, or Repair option.
6. Complete the wizard.
7. Repeat for the other architecture if it is installed.
8. Restart Windows.

The classic path works on both Windows 10 and Windows 11:

1. Open Control Panel.
2. Select Programs > Programs and Features.
3. Find the Visual C++ 2010 x86 and x64 entries.
4. Select one entry.
5. Choose Change.
6. Select Repair if offered.
7. Complete the repair.
8. Repeat for the other entry.
9. Restart Windows.

Not every installer exposes the same repair choices. Microsoft documents the general Windows repair process in Repair apps and programs in Windows.

How to tell whether this worked

The repair worked if:

• The program opens normally.
• The same error no longer appears.
• The program reaches its main menu or login screen.
• The Visual C++ installer completes without reporting a failure.

If the error changes to another VC++ 2010 filename, install or repair the complete runtime rather than copying that new file individually. The application may be missing several related files.

Fix 2: Repair or reinstall the affected application

If only one application fails, especially if the error started after an update or cleanup, the application’s own files are a strong suspect.

An application can deploy MFC files beside its executable instead of using the central Windows runtime directories. In that situation, repairing the Microsoft redistributable may not restore the private copy expected by the application.

Repair a Windows application

1. Open Start > Settings.
2. Select Apps > Installed apps on Windows 11.
3. On Windows 10, open Apps > Apps & features.
4. Find the affected application.
5. Open its menu or select the application entry.
6. Choose Advanced options if available.
7. Select Repair.
8. Start the application again.

If Repair is unavailable or does not help, use the application’s own installer:

1. Open Control Panel > Programs > Programs and Features.
2. Select the application.
3. Choose Change, Repair, or Modify if available.
4. Complete the vendor’s repair wizard.
5. Restart Windows and test the program.

Do not delete DLL files from the application directory before attempting repair. The installer may need to identify the existing installation and replace its files correctly.

Verify game files

For a game, use the launcher’s verification feature before reinstalling the entire game.

Steam explains that games can depend on secondary installers such as Visual C++ components. If a prerequisite installer was canceled, blocked, or removed, the game may fail during launch. Follow Steam’s launch troubleshooting guidance.

For Epic Games:

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

Epic documents this process in its file verification instructions.

If verification reports damaged files or does not resolve the problem, reinstall the game from its official launcher. The game’s installer may include the exact Visual C++ 2010 build and app-local files it requires.

Fix 3: Check whether antivirus software quarantined the file

Antivirus cleanup is a common cause when a program worked previously and suddenly stopped after a scan, update, or disk cleanup.

Do not restore a DLL simply because its name matches the error. First confirm that it came from the trusted Microsoft runtime or the official application installation.

In Windows Security:

1. Open Start.
2. Search for Windows Security.
3. Open Virus & threat protection.
4. Select Protection history.
5. Review recent detections.
6. Expand any item associated with the affected application or Visual C++ runtime.
7. Check the file path and detection details.
8. Restore it only when its origin is trusted and the file belongs to the expected installation.
9. If Windows Security offers Allow on device, use that only after verifying the file.
10. Reinstall the official runtime or application if the file was removed rather than quarantined.

Microsoft describes these actions in Protection History in the Windows Security app.

A safer repair after a quarantine event is often:

1. Record the detection and file path.
2. Remove or leave the untrusted copy quarantined.
3. Download the Microsoft redistributable from the official page.
4. Repair or reinstall the affected application.
5. Run another scan.

If antivirus software repeatedly removes a newly installed Microsoft package, investigate the detection before creating exclusions. A file with the correct name can still be tampered with or placed in an unsafe directory.

Fix 4: Check the file location and architecture

A file can exist and still fail because it is in the wrong directory, belongs to the wrong architecture, or depends on another missing DLL.

Understand the Windows directories

On 64-bit Windows:

• %windir%\System32 normally contains 64-bit system files.
• %windir%\SysWOW64 normally contains 32-bit system files.

The names are counterintuitive. System32 is the normal location for 64-bit files, while SysWOW64 is the normal location for 32-bit files. Microsoft explains this behavior in the File System Redirector documentation.

On 32-bit Windows, the x86 version normally uses %windir%\System32.

An application-local copy may instead be in a path such as:

C:\Program Files\AppName\

or:

C:\Program Files (x86)\AppName\

The exact application folder depends on the software.

Search for central copies

Open Command Prompt and run:

where.exe mfc100enu.dll

Possible results include one or more paths under System32 or SysWOW64. No result means the file is not on the current search path, but this command is not an exhaustive search for application-local copies.

Also inspect the folder containing the affected program’s executable:

1. Right-click the application shortcut.
2. Select Properties.
3. Open the Shortcut tab.
4. Select Open File Location.
5. Look for mfc100enu.dll and the related Visual C++ 2010 files.

Do not move a file from one Windows directory to another. A 32-bit DLL copied into the 64-bit location, or vice versa, will not solve an architecture mismatch.

Check the digital signature

For a centrally installed Microsoft runtime file:

1. Right-click the DLL.
2. Select Properties.
3. Open the Digital Signatures tab.
4. Select the signature.
5. Choose Details.
6. Confirm that Windows reports a valid signature from Microsoft.

An application-local file may be signed by the application vendor instead, depending on how it was deployed. An unsigned file from an unknown download source should not be treated as a valid replacement.

Check sibling files

In the same directory, look for related Visual C++ 2010 files such as:

• mfc100.dll
• mfc100u.dll
• mfcm100.dll
• mfcm100u.dll
• msvcr100.dll
• msvcp100.dll

Do not assume that the absence of one visible file proves it is the only problem. Reinstall the complete runtime or application package so that all dependencies are restored together.

Fix 5: Install pending Windows updates

Windows Update will not normally install the Visual C++ 2010 redistributable for an application, but it can repair operating-system components and compatibility problems that appeared after a system change.

On Windows 11:

1. Open Start > Settings.
2. Select Windows Update.
3. Choose Check for updates.
4. Select Download & install when updates are offered.
5. Restart when prompted.
6. Return to Windows Update and check again.
7. Test the affected application.

On Windows 10:

1. Open Start > Settings.
2. Select Update & Security.
3. Choose Windows Update.
4. Select Check for updates.
5. Install the available updates.
6. Restart Windows.
7. Test the application again.

Use Microsoft’s Windows Update instructions if the menu names differ on your build.

Windows Update is a supporting repair step, not a replacement for the Visual C++ 2010 package. If the application specifically requires VC10, install VC10.

Fix 6: Repair Windows components with DISM and SFC

Use DISM and System File Checker when multiple Windows components are failing, Windows features are damaged, or several unrelated programs report corrupted system files.

These commands normally repair Windows itself. They do not reliably restore an application’s private copy of mfc100enu.dll.

Run DISM first

On Windows 11:

1. Right-click Start.
2. Select Terminal (Admin).
3. Approve the User Account Control prompt.

On Windows 10:

1. Open Start.
2. Search for Command Prompt.
3. Right-click it.
4. Select Run as administrator.
5. Approve the User Account Control prompt.

Run:

DISM.exe /Online /Cleanup-Image /RestoreHealth

Wait for the operation to complete. Do not close the window while the percentage appears stalled.

Run SFC after DISM

After DISM completes successfully, run:

sfc /scannow

Wait until verification reaches 100 percent. Restart Windows and test the application.

A useful result is a message stating that Windows Resource Protection found no integrity violations, or that corrupted files were found and repaired. If SFC reports that it could not repair some files, restart Windows and run the same command again after confirming that DISM completed successfully.

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

Running SFC and DISM repeatedly by hand can leave you guessing what changed; Outbyte PC Repair offers a free scan that shows what it found, while repair is handled by the full version. It is optional, and reinstalling the affected application remains the definitive fix when the missing file belongs to that program.

Fix 7: Investigate a recent driver or system change

A driver reinstall is not a targeted repair for mfc100enu.dll. Consider this branch only when:

• Several unrelated programs began reporting “not designed to run on Windows” errors.
• The issue started immediately after a driver update.
• The affected software is a hardware utility.
• The software vendor says its runtime failure is related to a device package.
• Windows has recently experienced graphics, storage, or device instability.

Check Windows Update driver options

1. Open Start > Settings.
2. Select Windows Update.
3. Open Advanced options.
4. Select Optional updates.
5. Expand Driver updates if available.
6. Review the device and manufacturer.
7. Install an update only when it matches the hardware and timing of the problem.
8. Restart Windows.

Check Device Manager

1. Right-click Start.
2. Select Device Manager.
3. Expand the relevant category, such as Display adapters, Network adapters, or Sound, video and game controllers.
4. Right-click the device.
5. Select Properties.
6. Open the Driver tab.
7. Use Roll Back Driver if the problem began directly after that driver update and the button is available.
8. Otherwise select Update Driver.
9. Choose Search automatically for drivers.
10. Restart Windows and test the application.

For a vendor-specific driver, use the driver package supplied by the computer or hardware manufacturer. Do not remove a working driver merely because mfc100enu.dll is missing.

When identifying stale drivers manually means hunting through many device categories, Outbyte Driver Updater offers a free scan showing which drivers it identifies, while installation is handled by the full version. It is optional, and a driver change should remain a secondary investigation unless the timing clearly points to one.

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Fix 8: Use System Restore after a known system change

System Restore is appropriate when the error began immediately after a software installation, driver change, system update, or cleanup operation and a suitable restore point exists.

It can roll back system files, installed programs, drivers, and settings. It normally does not remove personal documents, photos, or other personal files, but review the affected programs before confirming the operation.

To start System Restore:

1. Press Windows + R.
2. Enter:

rstrui.exe

1. Press Enter.
2. Select Next.
3. Choose a restore point created before the problem began.
4. Select Scan for affected programs if available.
5. Review the changes.
6. Select Next, then Finish.
7. Allow Windows to restart.
8. Test the affected application.

You can also open Control Panel > Recovery > Open System Restore. Microsoft documents the feature in System Restore.

Do not use System Restore as the first response to a routine missing-runtime error. Install or repair the correct VC++ package first.

What not to do

Do not download a loose DLL from a random website

Random DLL download sites can provide:

• Malware or tampered files.
• The wrong x86 or x64 architecture.
• A build that does not match the application.
• A file with missing dependencies.
• An unsigned file that Windows or antivirus software rejects.
• A file that creates DLL search-order or hijacking risk.

A loose copy also does not repair the rest of the Visual C++ runtime. The safe sources are:

• The official Microsoft Visual C++ 2010 SP1 package page.
• Microsoft’s supported Visual C++ redistributable downloads page.
• The affected application’s official installer or repair process.

Do not copy the file blindly into System32

Copying a DLL into System32 is not a general repair method. It can place a 32-bit file where a 64-bit program expects a 64-bit file, or create a mixture of files from different runtime builds.

Application-local deployment is supported in some cases, but it must use the exact file supplied by the software vendor and match the application architecture. Microsoft’s MFC deployment guidance explains the distinction.

Do not run regsvr32 on this file

regsvr32 is intended for DLLs that expose registration entry points such as DllRegisterServer. It is not a general-purpose missing-DLL repair command.

Do not run:

regsvr32 mfc100enu.dll

There is no Microsoft-supported instruction to register this MFC resource DLL. An error stating that DllRegisterServer was not found confirms that registration is the wrong repair path. Microsoft documents the command’s purpose in regsvr32.

Do not install only the modern Visual C++ package

The Visual C++ 2015–2026 redistributable is not a universal replacement for Visual C++ 2010. Older Visual C++ runtimes remain separate side-by-side packages.

Install the VC++ 2010 SP1 redistributable requested by the application. Installing a newer runtime alone may leave mfc100enu.dll unavailable.

Do not expect Windows Features to install VC++ 2010

The Windows Features dialog does not normally provide the Visual C++ 2010 redistributable.

You can view it through:

1. Open Control Panel.
2. Select Programs.
3. Select Turn Windows features on or off.

Do not enable or disable random features to fix this error. Features such as .NET Framework components serve different purposes. Use the Microsoft redistributable installer or the application’s official installer instead.

If the official redistributable refuses to install

Try these steps in order:

1. Restart Windows.
2. Close the affected application and any installer windows.
3. Open Settings > Apps > Installed apps.
4. Search for existing Visual C++ 2010 x86 and x64 entries.
5. Use Repair or Modify if available.
6. Run the Microsoft installer again as an administrator.
7. On 64-bit Windows, verify that you are using the correct x86 and x64 installers.
8. Install pending Windows updates.
9. Restart again.
10. Repair or reinstall the affected application from its official installer.

If Windows reports that a newer version is already installed, repair the existing entry rather than downloading an unrelated DLL. If the runtime entry is damaged and cannot be repaired, the affected application’s installer may be the best supported way to restore its required runtime files.

Because Visual Studio 2010 is a legacy product, the Microsoft runtime page remains the authority for the available package and its documented compatibility information.

FAQ

Is mfc100enu.dll malware?

No. It is a legitimate Microsoft Visual C++ 2010 MFC localization component. However, malware can use the same filename, so verify the file path and digital signature. A copy from an arbitrary download site should not be trusted merely because the filename is correct.

Is mfc100enu.dll part of Windows?

It is not guaranteed to be present on every Windows installation. It may be installed by the Visual C++ redistributable, an application installer, or another Microsoft product.

What do mfc100.dll, mfc100u.dll, and mfc100enu.dll mean?

They are related Visual C++ 2010 MFC files. mfc100u.dll is associated with the Unicode MFC runtime, while mfc100enu.dll provides English-language MFC resources. mfc100.dll is another core MFC runtime component.

What are msvcr100.dll and msvcp100.dll?

They are Visual C++ 2010 runtime libraries used for C runtime and C++ runtime functionality. They are separate files but belong to the same VC10 generation.

Do I need Visual C++ 2010 or Visual C++ 2010 SP1?

Use the official Visual C++ 2010 SP1 redistributable package supplied by Microsoft. It is the practical supported package for this runtime family and includes the MFC security update.

Why does a 64-bit PC need x86?

Windows architecture and application architecture are separate. A 32-bit application uses the x86 runtime even when Windows itself is 64-bit. Install both packages when you run a mixture of old 32-bit and newer 64-bit software.

The file exists. Why does the error continue?

The copy may be in the wrong directory or have the wrong architecture. A dependency such as mfc100.dll, mfc100u.dll, msvcr100.dll, or msvcp100.dll may also be missing. Check the application directory, confirm the correct runtime architecture, and repair the complete package.

Should I replace the file manually?

Only when the software vendor’s official installer explicitly supplies the exact file for supported application-local deployment. Do not copy a file from a random download site into System32 or SysWOW64.

Should I run SFC for this error?

Run SFC when you suspect broader Windows corruption or several unrelated system files are failing. For a single application missing mfc100enu.dll, repair the Visual C++ runtime or the application first.

Does regsvr32 fix this DLL?

No. mfc100enu.dll is not documented as a COM or ActiveX server that needs registration. Re-registering it is not a supported repair.

When should I reinstall the application?

Reinstall it when only that application fails, its app-local runtime is missing, file verification reports corruption, or the problem began after an interrupted update. Use the official installer or launcher.

Information to collect before asking for help

If the error remains after repairing the runtime and application, record:

• The exact error message.
• The application or game name.
• Whether one program or many programs are affected.
• Windows 10 or Windows 11.
• Whether Windows is 32-bit or 64-bit.
• Whether the affected program is 32-bit or 64-bit, if known.
• The full path where mfc100enu.dll was found.
• The DLL’s file version and digital-signature status.
• The Visual C++ 2010 x86 and x64 entries shown in Installed apps.
• Any recent installation, update, cleanup, antivirus quarantine, or driver change.
• Whether the application has a Repair, Verify, or Modify function.
• The result of where.exe mfc100enu.dll.
• Any antivirus detection history associated with the file.

That information distinguishes a missing central runtime from a damaged app-local installation, an architecture mismatch, a quarantined file, or a dependency that is failing behind the message.

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