ModelSim executable not found in C:/intelFPGA/18.1/modelsim_ase/ Error.

The error message indicates that the ModelSim executable file cannot be found in the specified directory. This can occur due to a variety of reasons, such as incorrect installation or configuration settings.

Here are some possible solutions:

1. Check if the directory path is correct and make sure that ModelSim is installed in the specified directory.
2. Ensure that the environment variables for ModelSim are set correctly. To do this, go to Control Panel -> System -> Advanced System Settings -> Environment Variables and add the path to the ModelSim executable to the PATH variable.
3. Try reinstalling ModelSim and make sure to follow the installation instructions carefully.
4. If you are using a 64-bit operating system, make sure that you have installed the 64-bit version of ModelSim.

If none of these solutions work, you may need to contact Intel FPGA support for further assistance.