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

1. The file you downloaded is a compressed file with the ".zip" extension. In order to install it, first, double-click the ".zip" file and open the file. You will see the library named "Mcuninst.dll" in the window that opens up. This is the library you need to install. Drag this library to the desktop with your mouse's left button.

   

2. Copy the "Mcuninst.dll" library you extracted and paste it into the "C:\Windows\System32" directory.

   

3. If your system is 64 Bit, copy the "Mcuninst.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 "Mcuninst.dll" library.

   

4. 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.

   

5. 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 Mcuninst.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 Mcuninst.dll

   

6. 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 Mcuninst.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 Mcuninst.dll

   

7. You must create a new registry for the dynamic link library that you deleted from the registry editor. In order to do this, copy the command below and paste it into the Command Line and hit Enter.

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

   

8. 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 Mcuninst.dll library that we deleted.

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

   

9. You may see certain error messages when running the commands from the command line. These errors will not prevent the installation of the Mcuninst.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 Mcuninst.dll Library Into The Program Installation Directory 

1. First, you need to find the installation directory for the program you are receiving the "Mcuninst.dll not found", "Mcuninst.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 Mcuninst.dll library into the directory we opened up.

   

4. That's all there is to the installation process. Run the program giving the dll error again. If the dll error is still continuing, completing the 3rd Method may help fix your issue.

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

1. Press the "Windows" + "R" keys at the same time to open the Run tool. Paste the command below into the text field titled "Open" in the Run window that opens and press the Enter key on your keyboard. This command will open the "Programs and Features" tool.

   appwiz.cpl

   

2. The Programs and Features screen will come up. You can see all the programs installed on your computer in the list on this screen. Find the program giving you the dll error in the list and right-click it. Click the "Uninstall" item in the right-click menu that appears and begin the uninstall process.

   

3. A window will open up asking whether to confirm or deny the uninstall process for the program. Confirm the process and wait for the uninstall process to finish. Restart your computer after the program has been uninstalled from your computer.

   

4. After restarting your computer, reinstall the program.
5. You may be able to fix the dll error you are experiencing by using this method. If the error messages are continuing despite all these processes, we may have a issue deriving from Windows. To fix dll errors deriving from Windows, you need to complete the 4th Method and the 5th Method in the list.

Method 4: Fixing the Mcuninst.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. Paste the command in the line below into the Command Line that opens up and press Enter key.

   sfc /scannow

   

3. The scan and repair process can take some time depending on your hardware and amount of system errors. Wait for the process to complete. After the repair process finishes, try running the program that is giving you're the error.

Method 5: Fixing the Mcuninst.dll Errors by Manually 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