Method 1: Copying the Outlookui.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 "Outlookui.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 "Outlookui.dll" file you extracted and paste it into the "C:\Windows\System32" folder.

   

6. If your operating system has a 64 Bit architecture, copy the "Outlookui.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 "Outlookui.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 that will open up and hit Enter. This command will delete the damaged registry of the Outlookui.dll file (It will not delete the file we pasted into the System32 folder; it will delete the registry in Regedit. The file we pasted into the System32 folder will not be damaged).

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

   

9. 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 Outlookui.dll file'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 Outlookui.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 Outlookui.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 Outlookui.dll file that we deleted.

    %windir%\SysWoW64\regsvr32.exe /i Outlookui.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 Outlookui.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 Outlookui.dll File Into 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 "Outlookui.dll is missing", "Outlookui.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 Outlookui.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: Doing a Clean Reinstall of the Software That Is Giving the Outlookui.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. The Programs and Features window will open up. Find the software that is giving you the dll error in this window that lists all the softwares on your computer and "Right-Click > Uninstall" on this software.

   

3. Uninstall the software from your computer by following the steps that come up and restart your computer.

   

4. 4. After restarting your computer, reinstall the software that was giving you the error.
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 Outlookui.dll Error using the Windows System File Checker (sfc /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. 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 Outlookui.dll Errors by Manually Updating Windows 

Most of the time, softwares have been programmed to use the most recent dll files. If your operating system is not updated, these files cannot be provided and dll errors appear. So, we will try to solve 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.

Explanations on Updating Windows Manually 

1. Explanation on Updating Windows 10 Manually
2. Explanation on Updating Windows 8.1 and Windows 8 Manually
3. Explanation on Updating Windows 7 and Windows Vista Manually
4. Explanation on Updating Windows XP Manually