Method 1: Installing the Adrtddm6420.dll File to the Windows System Folder 

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 dll file from within it. So, first double-click the file with the ".zip" extension and open the file.
2. You will see the file named "Adrtddm6420.dll" in the window that opens. This is the file you need to install. Click on the dll file with the left button of the mouse. By doing this, you select the file.

   

3. Click on the "Extract To" button, which is marked in the picture. In order to do this, you will need the Winrar software. If you don't have the software, it can be found doing a quick search on the Internet and you can download it (The Winrar software 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 dll file to the desktop by clicking the "Ok" button.

   

5. Copy the "Adrtddm6420.dll" file and paste it into the "C:\Windows\System32" folder.

   

6. If your operating system has a 64 Bit architecture, copy the "Adrtddm6420.dll" file and paste it also into the "C:\Windows\sysWOW64" folder.

   NOTE! On 64 Bit systems, the dll file must be in both the "sysWOW64" folder as well as the "System32" folder. In other words, you must copy the "Adrtddm6420.dll" file into both folders.

   

7. 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.

   

8. Paste the command below into the Command Line window that opens and hit the Enter key on your keyboard. This command will delete the Adrtddm6420.dll file's damaged registry (It will not delete the file you pasted into the System32 folder, but will delete the registry in Regedit. The file you pasted in the System32 folder will not be damaged in any way).

   %windir%\System32\regsvr32.exe /u Adrtddm6420.dll

   

9. If you have a 64 Bit operating system, after running the command above, you must run the command below. This command will clean the Adrtddm6420.dll file's damaged registry in 64 Bit as well (The cleaning process will be in the registries in the Registry Editor< only. In other words, the dll file you paste into the SysWoW64 folder will stay as it).

   %windir%\SysWoW64\regsvr32.exe /u Adrtddm6420.dll

   

10. We need to make a new registry for the dll file 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 Adrtddm6420.dll

    

11. Windows 64 Bit users must run the command below after running the previous command. With this command, we will create a clean and good registry for the Adrtddm6420.dll file we deleted.

    %windir%\SysWoW64\regsvr32.exe /i Adrtddm6420.dll

    

12. If you did all the processes correctly, the missing dll file will have been installed. You may have made some mistakes when running the Command Line processes. Generally, these errors will not prevent the Adrtddm6420.dll file from being installed. In other words, the installation will be completed, but it may give an error due to some incompatibility issues. You can try running the program that was giving you this dll file error after restarting your computer. If you are still getting the dll file error when running the program, please try the 2nd method.

Method 2: Copying the Adrtddm6420.dll File to the Software File Folder 

1. In order to install the dll file, you need to find the file folder for the software that was giving you errors such as "Adrtddm6420.dll is missing", "Adrtddm6420.dll not found" or similar error messages. In order to do that, Right-click the software's shortcut and click the Properties item in the right-click menu that appears.

   

2. Click on the Open File Location button that is found in the Properties window that opens up and choose the folder where the application is installed.

   

3. Copy the Adrtddm6420.dll file into the folder we opened up.

   

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

Method 3: Uninstalling and Reinstalling the Software That Is Giving the Adrtddm6420.dll Error 

1. Open the Run window by pressing the "Windows" + "R" keys on your keyboard at the same time. Type in the command below into the Run window and push Enter to run it. This command will open the "Programs and Features" window.

   appwiz.cpl

   

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

   

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

   

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

Method 4: Solving the Adrtddm6420.dll Error Using the Windows System File Checker 

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 software giving you errors again.

Method 5: Fixing the Adrtddm6420.dll Error by Manually Updating Windows 

Some softwares require updated dll files from the operating system. If your operating system is not updated, this requirement is not met and you will receive dll errors. Because of this, updating your operating system may solve the dll errors you are experiencing.

Most of the time, operating systems are automatically updated. However, in some situations, the automatic updates may not work. For situations like this, you may need to check for updates manually.

For every Windows version, the process of manually checking for updates is different. Because of this, we prepared a special guide for each Windows version. You can get our guides to manually check for updates based on the Windows version you use through 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