Method 1: Copying the Dsp_test.dll Library to the Windows System Directory 

1. The file you are going to download is a compressed file with the ".zip" extension. You cannot directly install the ".zip" file. First, you need to extract the dynamic link library from inside it. So, double-click the file with the ".zip" extension that you downloaded and open the file.
2. You will see the library named "Dsp_test.dll" in the window that opens up. This is the library we are going to install. Click the library once with the left mouse button. By doing this you will have chosen the library.

   

3. Click the "Extract To" symbol marked in the picture. To extract the dynamic link library, it will want you to choose the desired location. Choose the "Desktop" location and click "OK" to extract the library to the desktop. In order to do this, you need to use the Winrar program. If you do not have this program, you can find and download it through a quick search on the Internet.

   

4. Copy the "Dsp_test.dll" library and paste it into the "C:\Windows\System32" directory.

   

5. If your operating system has a 64 Bit architecture, copy the "Dsp_test.dll" library and paste it also into the "C:\Windows\sysWOW64" directory.

   NOTE! On 64 Bit systems, the dynamic link library must be in both the "sysWOW64" directory as well as the "System32" directory. In other words, you must copy the "Dsp_test.dll" library into both directories.

   

6. First, we must run the Windows Command Prompt as an administrator.

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

   1. Open the Start Menu and type in "cmd", but don't press Enter. Doing this, you will have run a search of your computer through the Start Menu. In other words, typing in "cmd" we did a search for the Command Prompt.
   2. When you see the "Command Prompt" option among the search results, push the "CTRL" + "SHIFT" + "ENTER
   " keys on your keyboard.
   3. A verification window will pop up asking, "Do you want to run the Command Prompt as with administrative permission?" Approve this action by saying, "Yes".

   

7. Paste the command below into the Command Line window that opens up and press Enter key. This command will delete the problematic registry of the Dsp_test.dll library (Nothing will happen to the library we pasted in the System32 directory, it just deletes the registry from the Windows Registry Editor. The library we pasted in the System32 directory will not be damaged).

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

   

8. If you have a 64 Bit operating system, after running the command above, you must run the command below. This command will clean the Dsp_test.dll library'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 Dsp_test.dll

   

9. In order to cleanly recreate the dll library's registry that we deleted, copy the command below and paste it into the Command Line and hit Enter.

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

   

10. 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 Dsp_test.dll library (We deleted the damaged registry with the previous command).

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

    

11. 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 Dsp_test.dll library was installed successfully, you can still receive error messages like these due to some incompatibilities. In order to test whether your dll issue was fixed or not, try running the program giving the error message again. If the error is continuing, try the 2nd Method to fix this issue.

Method 2: Copying the Dsp_test.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 "Dsp_test.dll is missing", "Dsp_test.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 Dsp_test.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 Gives You the Dsp_test.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. After restarting your computer, reinstall the program that was giving the error.
5. You can fix 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 fix dll errors in Windows you will need to complete the 4th Method and the 5th Method in the list.

Method 4: Fixing the Dsp_test.dll Issue by Using the Windows System File Checker (scf scannow) 

1. First, we must run the Windows Command Prompt as an administrator.

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

   1. Open the Start Menu and type in "cmd", but don't press Enter. Doing this, you will have run a search of your computer through the Start Menu. In other words, typing in "cmd" we did a search for the Command Prompt.
   2. When you see the "Command Prompt" option among the search results, push the "CTRL" + "SHIFT" + "ENTER
   " keys on your keyboard.
   3. A verification window will pop up asking, "Do you want to run the Command Prompt as with administrative permission?" Approve this action by saying, "Yes".

   

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 Dsp_test.dll Error by Manually 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 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