ApiClient.dll is a file that is associated with the Microsoft Office API Client Library. It is required for running the Microsoft Office client.
Program can’t start because ApiClient.dll is missing from your computer
In order to fix the error message The program can’t start because ApiClient.dll is missing from your computer, when opening Office, follow the below suggestions: Let us see them in details:
1] Re-register DLL file
In case the DLL file is yet available on your device then re-registering the DLL file may fix the problem. Here is a quick guide to do: Open File Explorer using Win+E keyboard shortcut. Once it opens, go to the following location on your storage device – In the folder, search for the ApiClient.dll file. If the file is available inside the folder then you need to open an elevated command prompt. Inside the command prompt window, type the following command-line – Then press the Enter key to execute the code. Once it completes the procedure, restart your Windows device. Then open the Microsoft application and check if the problem is resolved now. Read: How to fix Missing DLL file errors.
2] Repair Office Installation
If re-registering the DLL file doesn’t work then try to repair the Office Installation. To do this, open Control Panel in your Windows device and then select the Programs and Features option. On the next screen, you will see a list of programs that are installed on the device. It allows you to uninstall, change, or repair the programs as per your requirements. Accordingly, choose Microsoft Office option from the list and then at the top, click the Change option. On the next page, select the type of repair you want to perform. The first one is Quick Repair. This option can fix the problem quickly and it doesn’t require internet service to execute the process. When the process gets finished, reboot your device and check if it resolved the issue. If the problem is now fixed then fine otherwise, go with the other method i.e. Online Repair. This repair method comparatively takes a little longer time and requires an internet connection to do it. So, moving ahead, select the radio button next to Online Repair > Repair. and then follow the onscreen instructions. Once it completes the process, restart your device and check if the APIClient.dll file is now available on the respective folder.
3] Uninstall and Reinstall Office
In case none of the above methods help to find the APIClient.dll file, you may need to uninstall and then reinstall Office. So, open the Windows Settings (Win+I) and then select Apps > Apps & features. Then move to the right pane and you will see a list that shows all the installed programs of Windows. Scroll a bit down and select Microsoft Office 365 > Uninstall. Again click on the Uninstall button if the system asks for the confirmation. Once the office app successfully gets removed from your device then install Office 365 on Windows PC again. Now restart your device and the problem would possibly be fixed now. I hope this guide helped you to solve the issue. If it does then let us know in the comment box which method helped you.