Method 1: Installing the A0004066.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 "A0004066.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 "A0004066.dll" library you extracted and paste it into the "C:\Windows\System32" directory.

   

6. If you are using a 64 Bit operating system, copy the "A0004066.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 "A0004066.dll" library into both directories.

   

7. In order to complete this step, you must run the Command Prompt as administrator. In order to do this, all you have to do is follow the steps below.

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

   1. Open the Start Menu and before clicking anywhere, type "cmd" on your keyboard. This process will enable you to run a search through the Start Menu. We also typed in "cmd" to bring up the Command Prompt.
   2. Right-click the "Command Prompt" search result that comes up and click the Run as administrator" option.

   

8. 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 A0004066.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 A0004066.dll

   

9. If the Windows you use has 64 Bit architecture, after running the command above, you must run the command below. This command will clean the broken registry of the A0004066.dll library from the 64 Bit architecture (The Cleaning process is only with registries in the Windows Registry Editor. In other words, the dynamic link library that we pasted into the SysWoW64 directory will stay as it is).

   %windir%\SysWoW64\regsvr32.exe /u A0004066.dll

   

10. 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 A0004066.dll

    

11. If the Windows version you use has 64 Bit architecture, after running the command above, you must run the command below. With this command, you will create a clean registry for the problematic registry of the A0004066.dll library that we deleted.

    %windir%\SysWoW64\regsvr32.exe /i A0004066.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 A0004066.dll library 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 A0004066.dll Library to the Program Installation Directory 

1. In order to install the dynamic link library, you need to find the installation directory for the program that was giving you errors such as "A0004066.dll is missing", "A0004066.dll not found" or similar error messages. In order to do that, Right-click the program'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 A0004066.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: Uninstalling and Reinstalling the Program That Is Giving the A0004066.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 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 that was giving the error.
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 A0004066.dll Issue by Using the Windows System File Checker (scf scannow) 

1. In order to complete this step, you must run the Command Prompt as administrator. In order to do this, all you have to do is follow the steps below.

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

   1. Open the Start Menu and before clicking anywhere, type "cmd" on your keyboard. This process will enable you to run a search through the Start Menu. We also typed in "cmd" to bring up the Command Prompt.
   2. Right-click the "Command Prompt" search result that comes up and click the Run as administrator" option.

   

2. Type the command below into the Command Line page that comes up and run it by pressing Enter on your keyboard.

   sfc /scannow

   

3. The process can take some time depending on your computer and the condition of the errors in the system. Before the process is finished, don't close the command line! When the process is finished, try restarting the program that you are experiencing the errors in after closing the command line.

Method 5: Fixing the A0004066.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