Method 1: Solving the DLL Error by Copying the Avidll99.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 "Avidll99.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 "Avidll99.dll" file you extracted and paste it into the "C:\Windows\System32" folder.

   

3. If your system is 64 Bit, copy the "Avidll99.dll" file and paste it into "C:\Windows\sysWOW64" folder.

   NOTE! On 64 Bit systems, you must copy the dll file to both the "sysWOW64" and "System32" folders. In other words, both folders need the "Avidll99.dll" file.

   

4. In order to run the Command Line as an administrator, complete the following steps.

   NOTE! In this explanation, we ran the Command Line on Windows 10. If you are using one of the Windows 8.1, Windows 8, Windows 7, Windows Vista or Windows XP operating systems, you can use the same methods to run the Command Line as an administrator. Even though the pictures are taken from Windows 10, the processes are similar.

   1. First, open the Start Menu and before clicking anywhere, type "cmd" but do not press Enter.
   2. When you see the "Command Line" option among the search results, hit the "CTRL" + "SHIFT" + "ENTER" keys on your keyboard.
   3. A window will pop up asking, "Do you want to run this process?". Confirm it by clicking to "Yes" button.

   

5. Paste the command below into the Command Line window that opens and hit the Enter key on your keyboard. This command will delete the Avidll99.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 Avidll99.dll

   

6. If you have a 64 Bit operating system, after running the command above, you must run the command below. This command will clean the Avidll99.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 Avidll99.dll

   

7. 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 Avidll99.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 Avidll99.dll file (We deleted the damaged registry with the previous command).

   %windir%\SysWoW64\regsvr32.exe /i Avidll99.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 Avidll99.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 Avidll99.dll File Into The Software File Folder 

1. First, you need to find the file folder for the software you are receiving the "Avidll99.dll not found", "Avidll99.dll is missing" or other similar dll errors. In order to do this, right-click on the shortcut for the software and click the Properties option from the options that come up.

   

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

   

3. Copy the Avidll99.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 Gives You the Avidll99.dll Error 

1. Push the "Windows" + "R" keys at the same time to open the Run window. Type the command below into the Run window that opens up and hit Enter. This process will open the "Programs and Features" window.

   appwiz.cpl

   

2. The softwares listed in the Programs and Features window that opens up are the softwares installed on your computer. Find the software that gives you the dll error and run the "Right-Click > Uninstall" command on this software.

   

3. Following the instructions that come up, uninstall the software from your computer and restart your computer.

   

4. 4. After restarting your computer, reinstall the software that was giving you the error.
5. This process may help the dll problem you are experiencing. If you are continuing to get the same dll error, the problem is most likely with Windows. In order to fix dll problems relating to Windows, complete the 4th Method and 5th Method.

Method 4: Solving the Avidll99.dll Problem by Using the Windows System File Checker (scf scannow) 

1. In order to run the Command Line as an administrator, complete the following steps.

   NOTE! In this explanation, we ran the Command Line on Windows 10. If you are using one of the Windows 8.1, Windows 8, Windows 7, Windows Vista or Windows XP operating systems, you can use the same methods to run the Command Line as an administrator. Even though the pictures are taken from Windows 10, the processes are similar.

   1. First, open the Start Menu and before clicking anywhere, type "cmd" but do not press Enter.
   2. When you see the "Command Line" option among the search results, hit the "CTRL" + "SHIFT" + "ENTER" keys on your keyboard.
   3. A window will pop up asking, "Do you want to run this process?". Confirm it by clicking to "Yes" button.

   

2. Paste the command below into the Command Line that opens up and hit the Enter key.

   sfc /scannow

   

3. This process can take some time. You can follow its progress from the screen. Wait for it to finish and after it is finished try to run the software that was giving the dll error again.

Method 5: Fixing the Avidll99.dll Errors by Manually Updating Windows 

Some softwares need updated dll files. 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.

Windows Update Guides 

1. Windows Update Guide
2. Windows 8.1 and Windows 8 Update Guide
3. Windows 7 and Windows Vista Update Guide
4. Windows XP Update Guide