Download the Lightroom 64-Bit DLLs package:
Error 'Could not call C function: private_load_AgCoreTech' while launching Lightroom on Windows
Error launching Lightroom on Windows
You encounter the error 'Could not call C function: private_load_AgCoreTech' while launching Lightroom or Lightroom 6 on Windows.
Solution: Download and install a DLL package to the Lightroom installation directory
This package contains two files: msvcr100.dll and msvcr80.dll.
Double-click the downloaded package to decompress it. If prompted, choose the option to extract all the files.
After you unzip the package, you see a folder named Lightroom_64-Bit_DLLs, which contains the following two files:
Copy these two files to C:\Program Files\Adobe\Adobe Photoshop Lightroom\.