Could NOT find Python3 (missing: Python3_EXECUTABLE Interpreter)

Sorry guys, I m totally not an IT guy, just tinkering around for a school project.

I am trying to build the OPC UA Library from Open62541 with a compiler shipped with MinGW:

Their GitHub Page:

In my opinion, they most probably target experienced CMake users with their manual to build the library, since the only chapter of their manual which describe the steps needed (for windows) is very scarce to say the least

At first, CMake hat problems with finding the compiler. After playing around with the enviroment variables which can be set in the CMake GUI (and then deleting it again), it found the correct compiler, but not the dll s, which also seem to be required. I added the path to those dll s in PATH. The compiler part seems to work now.

But it seems that python 3 executable is also required, since now I get the following error message:

CMake Error at tools/cmake/FindPackageHandleStandardArgs.cmake:137 (message):
  Could NOT find Python3 (missing: Python3_EXECUTABLE Interpreter)
Call Stack (most recent call first):
  tools/cmake/FindPackageHandleStandardArgs.cmake:378 (_FPHSA_FAILURE_MESSAGE)
  tools/cmake/FindPython/Support.cmake:795 (find_package_handle_standard_args)
  tools/cmake/FindPython3.cmake:138 (include)
  CMakeLists.txt:19 (find_package)


Configuring incomplete, errors occurred!

Python3 is installed on my system. The path to Python3 Executable is given in the Environment, but yet CMake still cannot find it.

Is this a bug of the CMake GUI?

Googled everything related, but no one is using the GUI so all topics related to this problem are useless to me

Problem solved, I guess. The CmakeCache.txt pointed the path of python3 to “EXECUTABLE NOT FOUND”. peculiar. I inserted the proper path and now it seems to work.