error: in triplet x64-windows: Unable to find a valid Visual Studio instance Could not locate a complete Visual Studio instance

As an AI language model, I do not have enough context to provide a specific solution to this error. However, below are some general steps that could help resolve this issue:

1. Make sure that you have Visual Studio installed on your system. If not, download and install Visual Studio from the official website.

2. Check if the environment variable 'VSINSTALLDIR' is set to the correct path of your Visual Studio installation. You can do this by opening a Command Prompt window and typing 'echo %VSINSTALLDIR%'. If the path returned is incorrect, update the environment variable.

3. If you have multiple versions of Visual Studio installed on your system, try specifying the version you want to use in the command. For example, if you want to use Visual Studio 2019, run the command 'cmake -G "Visual Studio 16 2019" ..'.

4. If none of the above steps work, try uninstalling and reinstalling Visual Studio and cmake.

5. If the issue still persists, seek help from online forums or contact the support team of Visual Studio or cmake.