Solution
DIAdem Versions Before 2017For DIAdem versions prior to 2017, this can be caused by a problem with the GPI Extension. To resolve this issue:
- Open DIAdem and go to Settings»Extensions»GPI Extensions.
- Click "+" button

3. Locate and select GfSICalc.dll file from the following directory (Making sure to change "DIAdem 2018" to the version you are using):
C:\Program Files\National Instruments\DIAdem 2018
4. Confirm that you see the information below and click Close.

5. Restart the program.
Note: Starting with DIAdem 2017 a new Calculator is provided that not defined in GFSICal.dll. It is not recommended to do these steps for DIAdem versions 2017 and higher since you will be activating the old calculator.