Method 1: Installing the Mfc40u.dll Library to the Windows System Directory 

1. The file you downloaded is a compressed file with the extension ".zip". This file cannot be installed. To be able to install it, first you need to extract the dynamic link library from within it. So, first double-click the file with the ".zip" extension and open the file.
2. You will see the library named "Mfc40u.dll" in the window that opens. This is the library you need to install. Click on the dynamic link library with the left button of the mouse. By doing this, you select the library.

   

3. Click on the "Extract To" button, which is marked in the picture. In order to do this, you will need the Winrar program. If you don't have the program, it can be found doing a quick search on the Internet and you can download it (The Winrar program is free).
4. After clicking the "Extract to" button, a window where you can choose the location you want will open. Choose the "Desktop" location in this window and extract the dynamic link library to the desktop by clicking the "Ok" button.

   

5. Copy the "Mfc40u.dll" library file you extracted.
6. Paste the dynamic link library you copied into the "C:\Windows\System32" directory.

   

7. If you are using a 64 Bit operating system, copy the "Mfc40u.dll" library and paste it into the "C:\Windows\sysWOW64" as well.

   NOTE! On Windows operating systems with 64 Bit architecture, the dynamic link library must be in both the "sysWOW64" directory as well as the "System32" directory. In other words, you must copy the "Mfc40u.dll" library into both directories.

   

8. First, we must run the Windows Command Prompt as an administrator.

   NOTE! We ran the Command Prompt on Windows 10. If you are using Windows 8.1, Windows 8, Windows 7, Windows Vista or Windows XP, you can use the same methods to run the Command Prompt as an administrator.

   1. Open the Start Menu and type in "cmd", but don't press Enter. Doing this, you will have run a search of your computer through the Start Menu. In other words, typing in "cmd" we did a search for the Command Prompt.
   2. When you see the "Command Prompt" option among the search results, push the "CTRL" + "SHIFT" + "ENTER
   " keys on your keyboard.
   3. A verification window will pop up asking, "Do you want to run the Command Prompt as with administrative permission?" Approve this action by saying, "Yes".

   

9. Let's copy the command below and paste it in the Command Line that comes up, then let's press Enter. This command deletes the Mfc40u.dll library's problematic registry in the Windows Registry Editor (The library that we copied to the System32 directory does not perform any action with the library, it just deletes the registry in the Windows Registry Editor. The library that we pasted into the System32 directory will not be damaged).

   %windir%\System32\regsvr32.exe /u Mfc40u.dll

   

10. If you are using a 64 Bit operating system, after doing the commands above, you also need to run the command below. With this command, we will also delete the Mfc40u.dll library's damaged registry for 64 Bit (The deleting process will be only for the registries in Regedit. In other words, the dll file you pasted into the SysWoW64 folder will not be damaged at all).

    %windir%\SysWoW64\regsvr32.exe /u Mfc40u.dll

    

11. We need to make a new registry for the dynamic link library in place of the one we deleted from the Windows Registry Editor. In order to do this process, copy the command below and after pasting it in the Command Line, press Enter.

    %windir%\System32\regsvr32.exe /i Mfc40u.dll

    

12. If you are using a 64 Bit operating system, after running the command above, you also need to run the command below. With this command, we will have added a new library in place of the damaged Mfc40u.dll library that we deleted.

    %windir%\SysWoW64\regsvr32.exe /i Mfc40u.dll

    

13. You may see certain error messages when running the commands from the command line. These errors will not prevent the installation of the Mfc40u.dll library. In other words, the installation will finish, but it may give some errors because of certain incompatibilities. After restarting your computer, to see if the installation was successful or not, try running the program that was giving the dll error again. If you continue to get the errors when running the program after the installation, you can try the 2nd Method as an alternative.

Method 2: Copying the Mfc40u.dll Library to the Program Installation Directory 

1. First, you need to find the installation directory for the program you are receiving the "Mfc40u.dll not found", "Mfc40u.dll is missing" or other similar dll errors. In order to do this, right-click on the shortcut for the program and click the Properties option from the options that come up.

   

2. Open the program's installation directory by clicking on the Open File Location button in the Properties window that comes up.

   

3. Copy the Mfc40u.dll library into the directory we opened.

   

4. The installation is complete. Run the program that is giving you the error. If the error is continuing, you may benefit from trying the 3rd Method as an alternative.

Method 3: Uninstalling and Reinstalling the Program that Gives You the Mfc40u.dll Error 

1. Open the Run tool by pushing the "Windows" + "R" keys found on your keyboard. Type the command below into the "Open" field of the Run window that opens up and press Enter. This command will open the "Programs and Features" tool.

   appwiz.cpl

   

2. On the Programs and Features screen that will come up, you will see the list of programs on your computer. Find the program that gives you the dll error and with your mouse right-click it. The right-click menu will open. Click the "Uninstall" option in this menu to start the uninstall process.

   

3. You will see a "Do you want to uninstall this program?" confirmation window. Confirm the process and wait for the program to be completely uninstalled. The uninstall process can take some time. This time will change according to your computer's performance and the size of the program. After the program is uninstalled, restart your computer.

   

4. After restarting your computer, reinstall the program that was giving the error.
5. This process may help the dll problem you are experiencing. If you are continuing to get the same dll error, the problem is most likely with Windows. In order to fix dll problems relating to Windows, complete the 4th Method and 5th Method.

Method 4: Fixing the Mfc40u.dll Issue by Using the Windows System File Checker (scf scannow) 

1. First, we must run the Windows Command Prompt as an administrator.

   NOTE! We ran the Command Prompt on Windows 10. If you are using Windows 8.1, Windows 8, Windows 7, Windows Vista or Windows XP, you can use the same methods to run the Command Prompt as an administrator.

   1. Open the Start Menu and type in "cmd", but don't press Enter. Doing this, you will have run a search of your computer through the Start Menu. In other words, typing in "cmd" we did a search for the Command Prompt.
   2. When you see the "Command Prompt" option among the search results, push the "CTRL" + "SHIFT" + "ENTER
   " keys on your keyboard.
   3. A verification window will pop up asking, "Do you want to run the Command Prompt as with administrative permission?" Approve this action by saying, "Yes".

   

2. Paste the command below into the Command Line that opens up and hit the Enter key.

   sfc /scannow

   

3. This process can take some time. You can follow its progress from the screen. Wait for it to finish and after it is finished try to run the program that was giving the dll error again.

Method 5: Fixing the Mfc40u.dll Error by Updating Windows 

Some programs need updated dynamic link libraries. When your operating system is not updated, it cannot fulfill this need. In some situations, updating your operating system can solve the dll errors you are experiencing.

In order to check the update status of your operating system and, if available, to install the latest update packs, we need to begin this process manually.

Depending on which Windows version you use, manual update processes are different. Because of this, we have prepared a special article for each Windows version. You can get our articles relating to the manual update of the Windows version you use from the links below.

Windows Update Guides 

1. Windows Update Guide
2. Windows 8.1 and Windows 8 Update Guide
3. Windows 7 and Windows Vista Update Guide
4. Windows XP Update Guide