Method 1: Copying the Msmdun80.dll Library to the Windows System Directory 

1. The file you are going to download is a compressed file with the ".zip" extension. You cannot directly install the ".zip" file. First, you need to extract the dynamic link library from inside it. So, double-click the file with the ".zip" extension that you downloaded and open the file.
2. You will see the library named "Msmdun80.dll" in the window that opens up. This is the library we are going to install. Click the library once with the left mouse button. By doing this you will have chosen the library.

   

3. Click the "Extract To" symbol marked in the picture. To extract the dynamic link library, it will want you to choose the desired location. Choose the "Desktop" location and click "OK" to extract the library to the desktop. In order to do this, you need to use the Winrar program. If you do not have this program, you can find and download it through a quick search on the Internet.

   

4. Copy the "Msmdun80.dll" library and paste it into the "C:\Windows\System32" directory.

   

5. If your system is 64 Bit, copy the "Msmdun80.dll" library and paste it into "C:\Windows\sysWOW64" directory.

   NOTE! On 64 Bit systems, you must copy the dynamic link library to both the "sysWOW64" and "System32" directories. In other words, both directories need the "Msmdun80.dll" library.

   

6. In order to run the Command Line as an administrator, complete the following steps.

   NOTE! In this explanation, we ran the Command Line on Windows 10. If you are using one of the Windows 8.1, Windows 8, Windows 7, Windows Vista or Windows XP operating systems, you can use the same methods to run the Command Line as an administrator. Even though the pictures are taken from Windows 10, the processes are similar.

   1. First, open the Start Menu and before clicking anywhere, type "cmd" but do not press Enter.
   2. When you see the "Command Line" option among the search results, hit the "CTRL" + "SHIFT" + "ENTER" keys on your keyboard.
   3. A window will pop up asking, "Do you want to run this process?". Confirm it by clicking to "Yes" button.

   

7. Paste the command below into the Command Line that will open up and hit Enter. This command will delete the damaged registry of the Msmdun80.dll library (It will not delete the file we pasted into the System32 directory; it will delete the registry in Regedit. The file we pasted into the System32 directory will not be damaged).

   %windir%\System32\regsvr32.exe /u Msmdun80.dll

   

8. 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 Msmdun80.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 Msmdun80.dll

   

9. 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 Msmdun80.dll

   

10. 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 Msmdun80.dll library that we deleted.

    %windir%\SysWoW64\regsvr32.exe /i Msmdun80.dll

    

11. If you did the processes in full, the installation should have finished successfully. If you received an error from the command line, you don't need to be anxious. Even if the Msmdun80.dll library was installed successfully, you can still receive error messages like these due to some incompatibilities. In order to test whether your dll issue was fixed or not, try running the program giving the error message again. If the error is continuing, try the 2nd Method to fix this issue.

Method 2: Copying the Msmdun80.dll Library to the Program Installation Directory 

1. First, you need to find the installation directory for the program you are receiving the "Msmdun80.dll not found", "Msmdun80.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 Msmdun80.dll library into this directory that opens.

   

4. This is all there is to the process. Now, try to run the program again. If the problem still is not solved, you can try the 3rd Method.

Method 3: Doing a Clean Reinstall of the Program That Is Giving the Msmdun80.dll Error 

1. Push the "Windows" + "R" keys at the same time to open the Run window. Type the command below into the Run window that opens up and hit Enter. This process will open the "Programs and Features" window.

   appwiz.cpl

   

2. The programs listed in the Programs and Features window that opens up are the programs installed on your computer. Find the program that gives you the dll error and run the "Right-Click > Uninstall" command on this program.

   

3. Following the instructions that come up, uninstall the program from your computer and restart your computer.

   

4. After restarting your computer, reinstall the program.
5. This method may provide the solution to the dll error you're experiencing. If the dll error is continuing, the problem is most likely deriving from the Windows operating system. In order to fix dll errors deriving from the Windows operating system, complete the 4th Method and the 5th Method.

Method 4: Fixing the Msmdun80.dll Error using the Windows System File Checker (sfc /scannow) 

1. In order to run the Command Line as an administrator, complete the following steps.

   NOTE! In this explanation, we ran the Command Line on Windows 10. If you are using one of the Windows 8.1, Windows 8, Windows 7, Windows Vista or Windows XP operating systems, you can use the same methods to run the Command Line as an administrator. Even though the pictures are taken from Windows 10, the processes are similar.

   1. First, open the Start Menu and before clicking anywhere, type "cmd" but do not press Enter.
   2. When you see the "Command Line" option among the search results, hit the "CTRL" + "SHIFT" + "ENTER" keys on your keyboard.
   3. A window will pop up asking, "Do you want to run this process?". Confirm it by clicking to "Yes" button.

   

2. After typing the command below into the Command Line, push Enter.

   sfc /scannow

   

3. Depending on your computer's performance and the amount of errors on your system, this process can take some time. You can see the progress on the Command Line. Wait for this process to end. After the scan and repair processes are finished, try running the program giving you errors again.

Method 5: Fixing the Msmdun80.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.

Guides to Manually Update the Windows Operating System 

1. Guide to Manually Update Windows 10
2. Guide to Manually Update Windows 8.1 and Windows 8
3. Guide to Manually Update Windows 7 and Windows Vista
4. Guide to Manually Update Windows XP