PTVS cant find Python interpreter?

I just copied my Flask project from one machine to another. I have same version of Python installed on both the machines. When I loaded the project in the new machine, it said my virtual environment is unavailable. So I initially tried to install it from requirements.txt file but it failed without any helpful error message.

So I deleted the virtual env in Visual Studio and tried to create another one. Now it complains that it cannot find any Python interpreters on my machine. I tried uninstall/reinstall Python but it didn't work. Also, the Python location is added in the PATH environment variable and all the modules in the requirements.txt file are downloaded from pip individually.

So the modules are installed, python is installed and the project is there but the virtual env won't setup because of the below reason. Any way that I can fix this ? This is PTVS15 and Python 3.6.1

Fixed it myself. I went ahead and added the environment manually by specifying the Python installation paths in the Add Environment tab. It took a while to detect the interpreter even in this way but it finally worked. I am now able to build my app.