Method 1: Copying the Core_2_1_0a.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 "Core_2_1_0a.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 "Core_2_1_0a.dll" file and paste it into the "C:\Windows\System32" folder.

   

3. If you are using a 64 Bit operating system, copy the "Core_2_1_0a.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 "Core_2_1_0a.dll" file into both folders.

   

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. Let's copy the command below and paste it in the Command Line that comes up, then let's press Enter. This command deletes the Core_2_1_0a.dll file's problematic registry in the Windows Registry Editor (The file that we copied to the System32 folder does not perform any action with the file, it just deletes the registry in the Windows Registry Editor. The file that we pasted into the System32 folder will not be damaged).

   %windir%\System32\regsvr32.exe /u Core_2_1_0a.dll

   

6. 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 Core_2_1_0a.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 Core_2_1_0a.dll

   

7. We need to make a new registry for the dll file in place of the one we deleted from the Windows Registry Editor. In order to do this process, copy the command below and after pasting it in the Command Line, press Enter.

   %windir%\System32\regsvr32.exe /i Core_2_1_0a.dll

   

8. Windows 64 Bit users must run the command below after running the previous command. With this command, we will create a clean and good registry for the Core_2_1_0a.dll file we deleted.

   %windir%\SysWoW64\regsvr32.exe /i Core_2_1_0a.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 Core_2_1_0a.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 Core_2_1_0a.dll File to 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 "Core_2_1_0a.dll is missing", "Core_2_1_0a.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 Core_2_1_0a.dll file into this folder that opens.

   

4. This is all there is to the process. Now, try to run the software again. If the problem still is not solved, you can try the 3rd Method.

Method 3: Uninstalling and Reinstalling the Software that Gives You the Core_2_1_0a.dll Error 

1. Open the Run window by pressing the "Windows" + "R" keys on your keyboard at the same time. Type in the command below into the Run window and push Enter to run it. This command will open the "Programs and Features" window.

   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. After restarting your computer, reinstall the software that was giving 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 Core_2_1_0a.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. 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: Solving the Core_2_1_0a.dll Error by 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