Method 1: Solving the DLL Error by Copying the Iis_u.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 "Iis_u.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 "Iis_u.dll" file and paste it into the "C:\Windows\System32" folder.

   

6. If you are using a 64 Bit operating system, copy the "Iis_u.dll" file and paste it into the "C:\Windows\sysWOW64" as well.

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

   

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. Paste the command below into the Command Line window that opens and hit the Enter key on your keyboard. This command will delete the Iis_u.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 Iis_u.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 Iis_u.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 Iis_u.dll

   

10. We need to make a clean registry for the dll file'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 Iis_u.dll

    

11. 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 file in place of the damaged Iis_u.dll file that we deleted.

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

    

12. 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 Iis_u.dll file was installed successfully, you can still receive error messages like these due to some incompatibilities. In order to test whether your dll problem was solved or not, try running the software giving the error message again. If the error is continuing, try the 2nd Method to solve this problem.

Method 2: Copying The Iis_u.dll File Into The Software File Folder 

1. First, you must find the installation folder of the software (the software giving the dll error) you are going to install the dll file to. In order to find this folder, "Right-Click > Properties" on the software's shortcut.

   

2. Open the software file folder by clicking the Open File Location button in the "Properties" window that comes up.

   

3. Copy the Iis_u.dll file into the folder we opened.

   

4. The installation is complete. Run the software that is giving you the error. If the error is continuing, you may benefit from trying the 3rd Method as an alternative.

Method 3: Uninstalling and Reinstalling the Software that Gives You the Iis_u.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. On the Programs and Features screen that will come up, you will see the list of softwares on your computer. Find the software 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 software?" confirmation window. Confirm the process and wait for the software 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 software. After the software is uninstalled, restart your computer.

   

4. After restarting your computer, reinstall the software that was giving the error.
5. You can solve the error you are expericing with this method. If the dll error is continuing in spite of the solution methods you are using, the source of the problem is the Windows operating system. In order to solve dll errors in Windows you will need to complete the 4th Method and the 5th Method in the list.

Method 4: Solving the Iis_u.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 software that you are experiencing the errors in after closing the command line.

Method 5: Fixing the Iis_u.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