Please follow the troubleshooting guide below to recover buttons and icons missing from CMM-Manager's UI.
Method 1: Recover by Loading the Default Layout
Click on the Layout icon located at the top right corner of the window then select Load.
Highlight Default Layout then click the Load button.
Method 2: Deleting the Layout Key from Windows Registry
Please follow steps below if the first method fails to resolve the issue or cannot be performed due to the missing Layout button.

This method requires the manipulation of Windows registry. Deleting or modifying an incorrect key may cause CMM-Manager and/or the Windows OS itself to become inoperable. Please consult with your IT department if you are not comfortable or do not have a permission to interact with the registry.
First, please close CMM-Manager if it is already opened then launch Registry Editor.
Locate Computer\HKEY_CURRENT_USER\SOFTWARE\QxSoft\CMM-Manager ####\Layouts and delete it (where #### is the CMM-Manager version that you are running).

For Nikon-branded CMM-Manager, please delete Computer\HKEY_CURRENT_USER\SOFTWARE\Nikon\CMM-Manager 3.#\Layouts instead.
Now close Registry Editor and open CMM-Manager.