Method 1: Fixing the DLL Error by Copying the Unzdll.dll Library to the Windows System Directory 

1. The file you will download is a compressed file with the ".zip" extension. You cannot directly install the ".zip" file. Because of this, first, double-click this file and open the file. You will see the library named "Unzdll.dll" in the window that opens. Drag this library to the desktop with the left mouse button. This is the library you need.

   

2. Copy the "Unzdll.dll" library file you extracted.
3. Paste the dynamic link library you copied into the "C:\Windows\System32" directory.

   

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

   

5. 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.

   

6. 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 Unzdll.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 Unzdll.dll

   

7. 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 Unzdll.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 Unzdll.dll

   

8. We need to make a clean registry for the dll library's registry that we deleted from Regedit (Windows Registry Editor). In order to accomplish this, copy and paste the command below into the Command Line and press Enter key.

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

   

9. 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 Unzdll.dll library that we deleted.

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

   

10. You may see certain error messages when running the commands from the command line. These errors will not prevent the installation of the Unzdll.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 Unzdll.dll Library Into 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 "Unzdll.dll is missing", "Unzdll.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 Unzdll.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 Install of the program That Is Giving the Unzdll.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. 4. After restarting your computer, reinstall the program that was giving you the error.
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 Unzdll.dll error with the Windows System File Checker 

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: Getting Rid of Unzdll.dll Errors by Updating the Windows Operating System 

Most of the time, programs have been programmed to use the most recent dynamic link libraries. If your operating system is not updated, these files cannot be provided and dll errors appear. So, we will try to fix the dll errors by updating the operating system.

Since the methods to update Windows versions are different from each other, we found it appropriate to prepare a separate article for each Windows version. You can get our update article that relates to your operating system version by using the links below.

Guides to Manually Update for All Windows Versions 

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