Method 1: Solving the DLL Error by Copying the Ctdlg91.dll File to the Windows System Folder 

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 file named "Ctdlg91.dll" in the window that opens. Drag this file to the desktop with the left mouse button. This is the file you need.

   

2. Copy the "Ctdlg91.dll" file and paste it into the "C:\Windows\System32" folder.

   

3. If your operating system has a 64 Bit architecture, copy the "Ctdlg91.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 "Ctdlg91.dll" file into both folders.

   

4. 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.

   

5. Paste the command below into the Command Line that will open up and hit Enter. This command will delete the damaged registry of the Ctdlg91.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 Ctdlg91.dll

   

6. If you are using a Windows version that has 64 Bit architecture, after running the above command, you need to run the command below. With this command, we will clean the problematic Ctdlg91.dll registry for 64 Bit (The cleaning process only involves the registries in Regedit. In other words, the dll file you pasted into the SysWoW64 will not be damaged).

   %windir%\SysWoW64\regsvr32.exe /u Ctdlg91.dll

   

7. You must create a new registry for the dll file that you deleted from the registry editor. In order to do this, copy the command below and paste it into the Command Line and hit Enter.

   %windir%\System32\regsvr32.exe /i Ctdlg91.dll

   

8. If you are using a Windows with 64 Bit architecture, after running the previous command, you need to run the command below. By running this command, we will have created a clean registry for the Ctdlg91.dll file (We deleted the damaged registry with the previous command).

   %windir%\SysWoW64\regsvr32.exe /i Ctdlg91.dll

   

9. 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 Ctdlg91.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 Ctdlg91.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 "Ctdlg91.dll is missing", "Ctdlg91.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 Ctdlg91.dll file.
4. Paste the dll file you copied into the software's file folder that we just opened.

   

5. When the dll file is moved to the software file folder, it means that the process is completed. Check to see if the problem was solved by running the software giving the error message again. If you are still receiving the error message, you can complete the 3rd Method as an alternative.

Method 3: Uninstalling and Reinstalling the Software That Is Giving the Ctdlg91.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 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. 4. After restarting your computer, reinstall the software that was giving you 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: Solving the Ctdlg91.dll Error Using 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. Paste the command in the line below into the Command Line that opens up and press Enter key.

   sfc /scannow

   

3. The scan and repair process can take some time depending on your hardware and amount of system errors. Wait for the process to complete. After the repair process finishes, try running the software that is giving you're the error.

Method 5: Fixing the Ctdlg91.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.

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