CMake cache
CMake caches variables and settings in the CMakeCache.txt file. When you load a project for the first time, this file is generated in the build directory (cmake-build-debug or cmake-build-release by default) according to the contents of CMakeLists.txt.
If required, you can open and edit CMakeCache.txt as a regular text file. For this, click 
in the CMake Tool Window or locate the file in the project tree.
You can view and edit values of CMake cache variables in the CMake profile settings.
Reset CMake cache
To reset the CMake cache without affecting the CLion cache, do one of the following:
Select from the main menu.
Click the
icon in the CMake tool window and select 
Reset Cache and Reload Project: 
Call Reset Cache and Reload Project using the Find Action dialog (Ctrl+Shift+A).