Method 1: Copying the Dec2oct.dll File to the Windows System Folder 

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 dll file from inside it. So, double-click the file with the ".zip" extension that you downloaded and open the file.
2. You will see the file named "Dec2oct.dll" in the window that opens up. This is the file we are going to install. Click the file once with the left mouse button. By doing this you will have chosen the file.

   

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

   

4. Copy the "Dec2oct.dll" file file you extracted.
5. Paste the dll file you copied into the "C:\Windows\System32" folder.

   

6. If your operating system has a 64 Bit architecture, copy the "Dec2oct.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 "Dec2oct.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 window that opens up and press Enter key. This command will delete the problematic registry of the Dec2oct.dll file (Nothing will happen to the file we pasted in the System32 folder, it just deletes the registry from the Windows Registry Editor. The file we pasted in the System32 folder will not be damaged).

   %windir%\System32\regsvr32.exe /u Dec2oct.dll

   

9. 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 Dec2oct.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 Dec2oct.dll

   

10. 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 Dec2oct.dll

    

11. If you are using a 64 Bit operating system, after running the command above, you also need to run the command below. With this command, we will have added a new file in place of the damaged Dec2oct.dll file that we deleted.

    %windir%\SysWoW64\regsvr32.exe /i Dec2oct.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 Dec2oct.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 Dec2oct.dll File to the Software File Folder 

1. First, you must find the installation folder of the software (the software giving the dll error) you are going to install the dll file to. In order to find this folder, "Right-Click > Properties" on the software's shortcut.

   

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

   

3. Copy the Dec2oct.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: Doing a Clean Install of the software That Is Giving the Dec2oct.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. 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 Dec2oct.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: Getting Rid of Dec2oct.dll Errors by Updating the Windows Operating System 

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.

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